I'm seriously thinking about saving some money up and getting a STS turbo kit for my Z28. In the mean time I wanna be getting the car ready for it. My question is should I keep the cats or will a off road y-pipe help or hurt the performance of the turbo?

 

I would just gut the cats. Also make sure there are not any exhaust leaks.

 

Upgrading the Y pipe probably isnt necissary, gutting the cat (or preferably replacing with a straight pipe) will only help though. I noticed much less throttle required to powerbrake the tires after I replaced my cat with a pipe.

 

Well as an STS owner who just had a cat come apart.... GET RID OF THEM!!!! My cat just shot crap into my turbo an wasted it.