I'm in the process of getting a Greddy turbo kit for my RSX, but can't decide on whether to get a custom 3'' exhaust or the Greddy Evo TT exhaust which is 2 3/4". Anybody have a ballpark figure on hp difference I could expect between the two? I don't mind a slight loss in power, but I think I would rather stay custom if were looking at a 15 to 20 hp difference. Any help would be great.

 

3" all the way

Anything smaller is way too restrictive. The K20 flow great with bigger piping. NA on mild setups can use 2.5-3" piping.