I should be getting my kit soon and the only exhuast mod I have is a performance muffler. It worx good but I wanted to have some custon piping made and I want to know what a good diameter for a stage stage 1 kit would be. I'm gonna get a resonator also, so it won't be too loud. I think the inlet of my muffler is 2.5, not really sure though, if I were to get say a 3 inch exhuast piping then would having a 2.5 inch muffler effect performance? Might get a bigger cat also.
#4453, "RE: What's a good exhuast size for turbo?" In response to Reply # 0
16" Exhaust would be a good size for turbo, but I don't think it would fit, so 3" should work ok. A 2.5" muffler will pose a restriction, go to a muffler shop with a mandrel bender and have them cutom make you a new cat-back. Shouldn't cost more than about $200. (What I paid for mine on my '92 GS)