I got RT Cats used (with over 9500 miles on them) and mated them to my Borla exhaust. I haven't had any problems yet. There is a hissing sound when I left off the gas and the rpm's drop to idle. I was told by my installer that it is air resonance and the sound produced is similiar to what helix test pipes give off when you decclerate. Sometimes I hear it sometimes I don't.

The Kinetix cats use a really good high flow cat (Carsound), but I didn't like the fact that their fitment in the past wasn't so good and it rattled on some cars (Kinetix may have fixed this by now). Also, their cats don't have the small attachments for the stock cat converter braces to connect to (it may rattle when you take your car full throttle). The RT cats and Crawford cats have this.

 

No, you got me thinking about that new Kinetix direct port inatke manifold...doesn't seem to give much gains for N/A G's but makes a world of difference for FI G's. Yeah, contact Tony (Hydrazine) for any spacer questions. They are his product. Good luck and keep me posted.

 

Just remember if you sell the car prior to 100,000 miles you may be required to return it to oem under Federal/State emission laws........even after the sale has transpired if found out.

Less likely now that many states only do check engine emission test [non dyno measurement] but what if the new owner moves to a state that requires visual inspection and dyno testing and the car fails because the cats are bad........they come looking for you to return [the cost thereof] the car to oem........they have you info via DMV.

One way to wash is to sell/trade to a dealer who is supposed to check those things......insulates you from some future liability, unless they catch it quickly.