Dude. That's the good s*** right there. That will NEVER crack. Good job!

Ok so first thing's first, I got the turbo outlet and downpipe off. Not much drama with that, I've done it before and it's relatively easy, although if you have hodor hands I could see why it would be a pain in the a**.

Here's a comparison of the Tomei pipe and stock O2 pipe Pretty significant difference! That's a pretty big bottle neck. Here's the ISR downpipe
Heres the 2.5 inch downpipe. Look at that surface rust! Additionally, Tomei engineered this outlet with having in mind that you are using a stud on the bottom-most hole, because you can't really fit a bolt in there. So I got an extra outlet stud and it all fits no problem. Place this stud at the notched part of the elbow. With that said, the downpipe is clocked incorrectly on my setup. The 3 hole flange is fine and mates to the Tomei unit, no problem. The flange that connects to the cat is at a weird diagonal whereas my cat flange is parallel to the ground. Also for some reason the downpipe flange is not on a flat plane. They put a stupid little curve at the end of the pipe. Doesn't make any sense to me. So my downpipe is now held to the cat with one bolt, just so I could secure it and get it partially going into the rest of the exhaust. Obviously it's a massive leak because the flange is clocked incorrectly. So I'll be taking this to the exhaust shop so they can chop and reweld it. Also I needed to take it there to get an o2 bung welded to the downpipe anyways. Strange that Isis doesn't already put a bung there.

After that, I'll finish sanding my brake booster, as it's always had rust on it from the previous owner having a master cylinder leak it looks like. I'm doing this to bide time until I go get a tune which will be sometime mid April. More to come!

I never had to mess with the cat on any of my SR conversion stuff, but I do know it get weird if you're trying to mix-and-match SR and CA exhaust stuff. After the cat it's all the same, so none of that matters, but I THINK everything between the turbo and cat isn't the same between the two. I don't have emissions where I live, so I've never had to worry about it. I've always had custom made downpipes that go straight from the turbo to the cat-back in one piece.

Soooo, it's possible this is just another CA/SR compatibility issue. As long as the cat is still good though, I'd just cut the flange on the cat and have it rotated and welded back on. Then if the cat fails later, a normal SR cat should bolt right in.

There's an O2 bung on the Tomei outlet pipe, why not use that? None of the downpipes I've seen have O2 bungs in them unless it's S14 stuff and it's for the post-cat O2 sensor.

Make sure you hit the brake booster with some rust converter after you get it sanded and cleaned, before you paint it. Just painting over the rust won't stop it from spreading.

Yeah, I'm just running a cat so that if I get pulled over, the cops can't give me too much s*** since at least I'm running a cat, and it'll help quiet down the car a little.

As for the bung, AEM recommends placing their sensor 18 inches from the head's exhaust port and it seems too close to do in the o2 outlet. This is recommended for the o2 sensor's lifespan. I'm not sure how much people take this to heart, as the o2 bung on the outlet seems to be the most logical place to put the sensor, and less of a chance of running into a leak since there's only the o2 gasket that might have a leak rather than o2 gasket + downpipe connection gasket. Still never really got why ppl wouldn't run it on the o2 outlet as that's where the stock location is.

As an added bonus, I took the car out for a little put around the street. Holy mother of god! That turbo whistle, I can finally hear it on my car! Now I don't know if it's because my downpipe has a large f*** gap next to the cat, lol. But damn the car has more bass and the turbo whistle is pretty damn loud, and that's with me not even getting on it or entering boost because of the tune! The car sounds absolutely mean but isn't overwhelmingly loud, just a deeper sound. Will get a proper judge of it once I get the cat flange rewelded, but so far I'm liking what I'm hearing.

Additionally, I replaced my oil return line as it was fraying against the steering wheel column. I put a steel braided line to replace the nylon braided one and I didn't quite fit it on properly so there's a very slow oil leak. So now I gotta get back under the car again, but I think I'll actually purchase some more nylon braided hose, as it's a bit more flexible underneath there so I can attach it to the oil pan a bit easier.

I've had issues with the sensor being too far away from the engine which makes closed loop and logging do funny things.

The only time I had issues with that location was when I had my cam timing off and the exhaust valve was opening too early, but then EVERYTHING was overheating. Once I got that fixed, I never had an issue again.

I'd put it in the stock location.

Open exhausts + turbo's = good sounds.

Yeah, maybe you can get it routed with the nylon so it doesn't rub?