I noticed when I first installed the aftermarket y-pipe that the car felt slower right off idle. Yet between ~2-3K rpm it was noticeably quicker. Not lightning fast but definitely had more "go" to it. Above 3K it was just noisy, I really could not tell if there was a performance difference. Having removed the aftermarket Y, I confirmed between around 2000 up to 3000 rpm it felt quicker as in the range performance noticeably diminished. If this were a car used strictly for racing I would definitely leave have left it in.

At 3000 rpm something strange happens in my car. The tone of the exhaust changes a lot, particularly under heavy load. Its seems to be either due to VVEL or CVTC, or perhaps the natural harmonics of the engine's design. It was inaudible with the factory Y pipe installed, but the aftermarket one brought about a completely new sound around 3K. Something to keep in mind for anyone with the VQ engine considering the Y pipe change. JBHorne did you notice this as well?

Sounds like a cat back and a nice intake is what's best for these cars.

I didnt lose any bottom with hfc.actually gained some.hfc,catback,intake...im done with my exhaust.no need to mess with it anymore.drives so good now.no drone at crusing speeds.great sound.no loss of power at any rpm....

That's great, glad you are satisfied with your set up.

On a side note, about those factory heat shields...you want the exhaust gases to be hot, as this helps the engine push those gases out the end. Cooler air is heavier, which causes the engine to work harder to get rid of the gases. Think about the sound of a cold start vs. a warmed up engine...just food for thought.

Could always wrap the exhaust...

Anyone seen or heard of anyone going the true dual route? Any one (read:all of you) smarter than I know if it would help or hinder HP and TQ at the wheel?

Has anyone installed the 1320 resonated test pipes? They're pretty inexpensive on eBay plus there's a coupon till tomorrow (PHLDAYTEN).

Fail! After I bought them on eBay I realized they're cheaper directly through their website.

Keep in mind that if you're in California, the only Cats approved are either OEM, or CARB-approved aftermarket (and there are few to zero options there regarding CC's) a CARB-approved cat will have a metal badge that will allow the car to pass a visual inspection. Generally, ANY aftermarket cat in CA will trigger suspicion and (oftentimes) a FAIL on the visual inspection, unless you have a savvy inspector who knows what to look for. Most of them are just afraid be being busted for passing cars that shouldn't be, and are reasonably paranoid as the state has harshly cracked-down on smog inspecting stations...Essentially, to get the CARB certification a huge sum of money has to be paid by the part mfg to the California Air Resources Board....