do fmax downpipes run 2.5 inches thru the whole thing, does any part of it taper to a smaller diameter to fit with oem catalytic converters? or do you just have to depend on the flanges matching up? should the oem cat be smaller in diameter than 2.5 ?

planning for the fmax t3/t04b turbonetics for accord 98

since it is a direct bolt on turbokit , i am wondering how the bolt on works between the cat and the Dpipe

 

i doubt it. if your running turbo you don't want to keep any part of the stock exhaust system since it is so small. the stock cat is probably like 2.0 inch diameter, that will kill power and defeat the purpose of your 2.5-3.0 exhaust after the cat.