I am doing my first swap and installing a GSR into my civic Ex. I was reading up on the thread regarding turbocharging. Everyone saids to get 3" exhaust system and go for the Thermal R&D. My friends are not fans of Themal, I wanted to know if 2.5" cat-back can be used?

Doesn't really matter what you think the muffler sounds like because they are all sounding very similar once you have the turbo on your car. 2.5" will work, but the bigger the better. I like the 3" Apex'I N1, the 3" Thermal R&D Turbo Exhaust, or my personal fav the www.kteller.com 3" exhaust kit + muffler of your choice.

3" is best 2.5 will work.. you can go to a muffler shop get a 3" bended and but a canaster of your choice and bolt it on i did that and paid $300 for a full cat back..
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