Is this correct?
Turbo housing -> short collector-piece -> 02sensor -> downpipe -> cat -> exhaust


And when getting a turbo-back exhaust, basically it only replaces the downpipe and exhaust, right? The 02 piece and short collector are still only 2.x" even if you get a 3" turbo-back exhaust like RMRs, right?

I'm looking at the RMR turboback exhaust but I'm curious what it replaces and what it leaves alone.

 

the order is header, turbo, O2 housing/diffuser, downpipe/frontpipe, cat, midsection, axle back/muffler.

Cat-backs will replace the exhaust from the cat out, turbo back's will replace the exhaust from the O2 housing out. In either exhaust the O2 housing will still remain stock, however there are companies making exhaust systems which include a new O2 housing.

 

Okay thanks!