Tonger

I've got the p0430 and p0420 catalytic converter codes in a heavily tracked car and suspect that they're probably ready for replacement. It looks like the majority of aftermarket systems run the 'x' crossover pipes. However, it doesn't look like the factory ever ran these 'x' pipes even in racing trim.

There is a strongly worded post from Fabspeed (Post #67 in below link) in 2006 saying the 'x' pipes actually lose power compared to the crossover but this seems to be all that they offer now. Has the general opinion changed or is there now dyno proof of improved performance?

https://rennlist.com/forums/996-gt2-...r-a-gt3-5.html

http://www.fabspeed.com/porsche-996-...rt-cat-x-pipe/

Thanks very much!