If u already have a cat back high performance exhaust y would someone wanna mod their cats..
Isnt the cats already mod for high performance cat back exhaust?
eg. Fuji legalis-R and Crawford cats?????

Also any have the Gruppe-s Y pipe? How would u rate it? How would u compare it to fuji's y pipe?

thanks..

 

Fuji, Gruppe S and UT Y pipes are relatively the same. I have the JIC Y pipe which is a straighter design than all 3 of those. I have crawfords too.

 

Nope. Cat-back means the exhaust starts after the cats.