Originally Posted by Tim B.
I have a Challenge Street x-pipe(no secondary cats, just primary) and a Gintani Race rear section/muffler. Was considering going to a Challenge Race x-pipe that removes the primaries.
If you do make sure you get a tune to turn off the CEL light from the removal of the cats. I have the Challenge Sport X-pipe on my car with a Remus race cat-back muffler.