I am going to install a turbo in my car soon, and need to replace the factory cat with an aftermarket highflow one. I hav a 1.7L, and I need the one with dual O2 bosses for my O2 sensors. I am looking at model # 91065, which is a smaller one, but I want to make sure its not too large for...I'm really not sure what size I should get....Anyone? (PS - don't reply and say "go catless," as that is not what I want to do).

 

I would realy go to ebay look for a 3" catco you can score one for about 35 bucks and have your local muffler shop weld her on. any thing under 3 will rob your power big time whn your boosted!