When I bought it in Sept 2015 it had just came off of a 3 year lease and had 52k miles. I put almost 73k on it in the 5+ years I drove it. It was stock except for the intake, exhaust, Uprev tune and aftermarket fog lights. The only two issues I experienced were the P0024 DTC at 60,400 miles that led to the oil jet/timing chain recall work being performed (at no cost to me) and the recurring P0420 cat code which seems to plague several of our members. With that said, I was going to continue driving it, as the car was running great and I was totally satisfied with it. However, with the current interest rates at all-time lows and due to some upcoming maintenance items, I decided to reassess keeping my car. The O2 extender was a temporary fix to address the P0420 DTC so that I could pass NC emissions this year. Eventually the manifold (probably both of them) will need to be replaced. I had also bumped a small deer which cracked my grill and scuffed the front fascia. Because I drive a lot on the interstate, the windshield had a lot of pock marks and was getting to the point of needing replacement. Both fog lights had busted lenses. The strut towers needed to be rebuilt, all of the fluids except the AT were due for a change, and my tires were getting close to needing replacement. One of the tires had developed a small leak, so I was having to add air about once a week. The gas cap door recently started to act up; sometimes I had to lock/unlock the car door a few times before it would release. In light of all this, I decided to sell the car and get something else. I just wanted to share my thoughts and experience on owning it over the 5+ years and comment on some of the more common threads I was involved with relating to this model.

Exhaust system…if I had to do this over again, I would’ve saved the original set up instead of chopping it up. This way I could’ve reinstalled the stock system and sold the aftermarket parts and recouped some of the money spent. It wouldn’t have been worth the time and effort for me to do it after the fact, so I decided to leave the X-pipe exhaust and sport mufflers on the car…lesson learned.

Intake…I did install the HPS silicone hoses which, according to their website, netted an additional 9 – 10 HP at the wheels. In a car already making 420 HP at the crank I really couldn’t tell a difference, even after it was tuned. I had saved the stock intake hoses, so those went back on the car when I sold it.

Uprev tune…I believe this car is tuned conservative from the factory, and can benefit from a custom tune with exhaust and intake mods, especially now with new support available in the way of headers, diff swaps and VVEL tuning tables. I was able to flash back to stock before selling it, and in accordance with Uprev’s latest policy on license updating, I installed the updated license back to the cable, which allows me to use it again or sell it.

Battery…personally I never experienced any of the battery draining issues that seem to plague a few of our members, so I never performed the alternator wire mod. My main commute is 25 miles at a time, back and forth to work. In the 5 years I had my car, I replaced the battery twice. First time was in 2016, when the factory battery finally crapped out. Next time was this past spring 2020. I did on rare occasion experience the “click” mentioned in conjunction with this issue when attempting to start the car. It happened so infrequently that I never did anything about it. Maybe the start button wasn’t getting a good connection?

Fog lights…mine seemed to be a bullseye for rocks and other debris. I’m not sure it this was by design, as I never had issues with fog lights on my other vehicles. Wonder if other folks have the same issues with theirs. I replaced them twice in 5 years and was needing to replace them again when I sold the car.

Antenna…definitely a must do upgrade if you’re getting crappy reception; mainly pre 2014 models. As you all know I did a write up on this.

Catch cans…I installed these to start with. I was trapping some oil so I thought maybe this was a worthwhile mod. However, when I replaced my PCV valves, I noticed a drop in oil levels in my cans. Turns out my old PCV valves were leaking by so I ended up removing the cans and reinstalling the original hoses. For my driving style I wasn’t trapping enough oil to mess with maintaining them. On a side note, oil consumption is a function of driving habit, so if you do a lot of racing around and/or WOT’s you might want to install the cans.

Gas/catalytic converter…I tried running ethanol free gas for a while. However, while it’s supposed to help with reducing carbon deposits on the intake valves and improve gas mileage, I found out that it’s best to stick with oxygenated fuel for exhaust systems with three way catalytic converters and computerized closed loop feedback. That fuel burns cleaner and is designed for maximum performance with that type exhaust. I am partially convinced that I started getting my P0420 DTC because of the e-free gas. It doesn’t burn as clean and the extra soot probably coated the catalyst material over time, causing the efficiency threshold to drop below setpoint. On a side note, I never had any issues with the passenger side; only the driver’s side which was odd. Most M56 owners I’ve seen on this forum and on Facebook seem to have issues with only the driver’s side as well. The driver’s side has a baffle installed in between the manifold and secondary cat. The passenger side does not. I discussed this in a thread a while back about a possible connection to the P0420 but I don’t think an explanation was ever found.

Anyway, I want to thank those who responded to various posts over the years for your feedback and advice. It is truly a pleasure to be a part of this forum, as it is by far the best resource for anything Nissan/Infiniti. As a now former owner I am still available as a reference for anything M56 related. The above comments should not be construed as fact; only my 2 cents worth. I only offer the comments based on my personal experience with my car.

I do have the following items from my car if anyone is interested:
New replacement set of OEM style fog lights.
Uprev tuning cable with updated license installed.
Black HPS silicone intake hoses with box and all paperwork and accessories.
The set of secondary cats that were cut out when I installed my X-pipe. I debated on using these as primary cats if I decided to install headers.
Sheet metal cross member piece that bolts under the mid pipe. I had to remove it because the X-pipe ran a little lower than the frame.

Brat...after all that....I have about 45k on my 2012 M56, so I expect to be in your shoes in 3-4 years.

but....

WHAT are you getting now? What to replace these cars with if not a high end AMG? And who wants that headache? I am at a loss as to what I will replace my car with at any reasonable value.

Strut towers? Can you go deeper into this?

As an aside, sad to see you go - you've been a good resource for me in here and in the Facebook group. Good luck with the next vehicle.

paranoidjack wrote: ↑

Fri Jan 15, 2021 8:56 pm

Brat...after all that....I have about 45k on my 2012 M56, so I expect to be in your shoes in 3-4 years.

but....

WHAT are you getting now? What to replace these cars with if not a high end AMG? And who wants that headache? I am at a loss as to what I will replace my car with at any reasonable value.

There's several I looked at. I wanted to stay with a sedan. I only buy one owner used cars with a proven service record. I can't afford the ones I like brand new, plus they depreciate so much after a few years. As much as I like the AMG, BMW M Series and Audi S6/7/8, I'm leery of buying used German cars, plus taking on the higher insurance and maintenance costs that go with them. Back in my high school days ('79 - '81) I drove a Camaro. American muscle was the king. Chargers, Challengers, Dusters, Mustangs, Firebirds, Camaro's, Nova's, Chevelle's were what we all drove. There were a few Volkswagen Scirocco's, Datsun 260z's and 280z's in there too. American muscle is doing well these days, with the Mustang GT's, Scat Packs, Camaro LT1, etc. With that said, I decided to go back to my roots. Since I wanted a performance sedan that is close to the M56 performance-wise, I looked at the Lincoln Continental, Chevy SS and Dodge Charger Scat Pack. Then I drove a 2011 CTS-V that a buddy at work had for sale. His had a stage 2 performance package installed that dyno'd at 756hp to the wheels. Holy cow that thing was awesome! So, I found a pristine garaged 2014 Cadillac CTS-V in Red Obsession fully loaded with every option you could get back then. One owner who leased it and kept it as a CPO after the lease. Regular maintenance performed since day 1 up until it was sold to me. So much aftermarket support for these cars too. My insurance is actually a little cheaper, which surprised me. It is taking some getting used to. It drives more like a Corvette because of the 19" staggered low profile tires. The Recaro seats hug you more, which is new for me. I'm learning how to navigate through the CUE screen interface. It's not the greatest system but it'll do. It's a whole different car than the M. Even though it's 2 years newer it doesn't have some of the luxury features that the M has...but that's ok.

Shanehsmp wrote: ↑

Sat Jan 16, 2021 7:57 am

Strut towers? Can you go deeper into this?

As an aside, sad to see you go - you've been a good resource for me in here and in the Facebook group. Good luck with the next vehicle.

Thanks man I appreciate it!

I've had a rattling noise coming from the front end, mainly noticeable when cruising at low speed like through the neighborhood. The strut bushings are worn. Instead of replacing the whole tower, they make a rebuild kit. They quoted me $1200 to install it.

On your rattling noise coming from the front end you might try the sway bar links; they are comparatively cheap and easy. My 2012 M56 with 60k miles had bad ones, and my noises went away after replacing the links. Good luck.

Good luck with the next ride. I'm potentially interested in the HPS intake tubes and the Uprev license. What are you looking to get? I'm located in Colorado

daniel_fx50s wrote: ↑

Sun Jan 17, 2021 5:41 pm

Good luck with the next ride. I'm potentially interested in the HPS intake tubes and the Uprev license. What are you looking to get? I'm located in Colorado

Thanks man, PM sent.

Nissan1968 wrote: ↑

Sun Jan 17, 2021 9:40 am

On your rattling noise coming from the front end you might try the sway bar links; they are comparatively cheap and easy. My 2012 M56 with 60k miles had bad ones, and my noises went away after replacing the links. Good luck.

Thanks man I appreciate the info! I just went by what the technician said when they inspected the front end. He may have also mentioned the sway bar but I don't remember.

armybrat wrote: ↑

Mon Jan 18, 2021 6:21 am

daniel_fx50s wrote: ↑

Sun Jan 17, 2021 5:41 pm

Good luck with the next ride. I'm potentially interested in the HPS intake tubes and the Uprev license. What are you looking to get? I'm located in Colorado

Thanks man, PM sent.

Doesn't look like I can access PMs since my account is so new. Are you on the FB group at all? I can message you there

armybrat wrote: ↑

Mon Jan 18, 2021 6:21 am

daniel_fx50s wrote: ↑

Sun Jan 17, 2021 5:41 pm

Good luck with the next ride. I'm potentially interested in the HPS intake tubes and the Uprev license. What are you looking to get? I'm located in Colorado

Thanks man, PM sent.

DM sent on FB!

Vic Hardy on Facebook. Haven't seen anything on messenger.

armybrat wrote: ↑

Mon Jan 18, 2021 9:58 am

Vic Hardy on Facebook. Haven't seen anything on messenger.

Open messenger and click "Message Requests". Sometimes they come through as hidden

Congrats on acquiring the new car.

I agree that Infiniti Ms can be pretty disappointing for people that like to extensively modify their vehicles, but I'm glad that you find that it wasn't all bad and that there are things you probably miss about your M56x.

Hopefully whatever forum you join will match the nicoclub experience.

Stay safe out there.

EdBwoy wrote: ↑

Tue Jan 19, 2021 3:05 pm

Congrats on acquiring the new car.

I agree that Infiniti Ms can be pretty disappointing for people that like to extensively modify their vehicles, but I'm glad that you find that it wasn't all bad and that there are things you probably miss about your M56x.

Hopefully whatever forum you join will match the nicoclub experience.

Stay safe out there.

Thanks for the kind words. I really enjoyed my experience with this car. I knew that there wasn’t a whole lot of mods to be done performance wise with the V8, and I was ok with it. I bought it for the luxury and the V8 was a bonus. I would’ve kept it as a project car but I don’t have a separate garage or shop much less a lift a lift to do that kind of work, so I decided to sell it and use the cash on mods for the next ride.

I do miss some features that are not available in the Caddy. Phone Bluetooth only; no audio bluetooth. It does have a USB and hard drive space for music though, so I just leave my memory stick in the port. No blind spot detection or lane assist, but it does have parking assist (beeps if you’re too close when pulling in the garage, etc.) No adaptive cruise control; just on/off/set/resume. The CUE infotainment set up is not as good as the M’s.

There are a few CTS-V forums out there; I will snoop around and join one soon. I joined a few Infiniti forums when I got my M but this one is by far the best hands down. I appreciate all of the info and hard work you guys do in maintaining this site, as well as the YouTube videos. Thanks again for the experience. I may chime in on occasion if I can contribute based on my experiences.
I sold my catch cans and HPS hoses. I still have the Uprev cable and license, secondary cats (60k miles) and fog lights. I also have a pair of used K&N filters (from another airbox set I bought). They just need to be cleaned. I know you were looking for exhaust manifolds; if you or anyone else can use the secondaries or other items PM me.