OEM catalytic converter is done
 

I have the berk high flow cat. I would recommend that. I decided to swap my test pipe to that to help with emissions (started caring about environment and hate the test pipe smell). Improves power, but not sure how long it will last. I track my car regularly and have had it for like 3+ years with no check engine lights.

Don't know why not. It should slide right in.

I recall the Speed Academy guys in Toronto ran a high flow cat in front of their Tanabe Medalion Touring exhaust when they were street driving their S2000 to and from the track. They seemed to get to the track frequently with this setup and didn't seem to be babying the car.

I'm running the Berk 63.5mm high flow cat in my street car. Passed Ohio smog check the three times I had it checked. Not sure how you're passing California smog with your cat-delete setup.

-- Chuck

I replaced my OEM cat with the EVS Tuning 70mm one, to be honest I noticed a better difference with that than I did replacing the stock exhaust to a single. I passed emissions too, but I havent had it on for very long.

My Berk has been fine for years, no light.

I can sell you mine (OEM AP2) that had 63k miles on it... $150 + shipping

I toasted my stock cat after about a dozen track days. The first brick inside the cat came loose and smashed into the O2 sensor and rattled around. It didn't help that after about 8 track days, I installed a Hondata K-Pro and leaned out the A/F about half a point (from ~11.0 to 11.5). A buddy had a used OEM one that he took off when his car became a track-only car which is now on my car.

Cats are going to be wear items on the track. Well, they are wear items in DD use too, but expected to last 100k miles not getting beat on at the track. I'm in the anti test pipe camp too. A high flow cat frees up some power and still provides most of the emissions reduction. And it doesn't stink out and poison everyone driving behind you.

All catalytic converters, including HFCs, will fail after pro-longed track use. The cores are a wear item when subjected to track use and will eventually get brittle and disintegrate. There's actually a video of an S2k shooting an HFC core out its exhaust on track.

I would say, swap a test pipe for track use, and keep the catalytic for smog purposes. Or, if you're willing to treat it as a disposable wear item, get an HFC as a cheaper option. Don't bother with an OEM cat - it will just fail again. They don't hold up to track use very well at all.

I'm not a fan of the test pipe stink either, but i've been finding that my track rat now sees 85/15 track/street use with about 3000 miles logged per year now. I find it a "minimal" evil comparatively versus if it were a DD.

Still have the OEM AP2 cat?

As an update, mine has since failed. The core wore around the edges and was able to rotate diagional with respect to exhaust flow.