I've been reading here and a little confused by the terms. I remember on my old car, it was turbo, downpipe, than cat-back exhaust.

1) So in the evo there is an 'extra' part between the downpipe and turbo, called 02 housing?

2) If I install a downpipe/02 housing for my current evo with a greddy 80 mm catback and stock turbo, can I eventually stick my planned gt35r and connect it to the same 02/Downpipe?

Or would I need to change only the 02 housing for the correct gt35 exhaust diameter (this is what I'm betting)

Thanks,
Tom

 

Its my understanding that on a stock evo it goes:

exhaust manifold -> turbo -> o2 housing -> downpipe -> cat -> catback