Just bought a 90 Integra and CAI already done, looking for exhaust now, would a 4-2-1 header, with no cat and 2.5 pipe all the way back to a muffler be a back pressure problem or should I be ok, has the 1.8 in it now, future is GSR motor

 

i dont see how, i have a 90 with a 4-2-1 header and cat back with cat and its sweet. I dont see how ur set up would cause a bottle neck in the system since u are deleting the cat which is the main bottle neck in a exhaust. Now if u plan on making gobs of power the 2.25 will need to be larger but for right now its fine and if u went bigger would lose low-end power

 

The 2.25 inch exhaust will probably be more suitable for your setup.
BTW, how strict are the emissions were you live? Might want to reconsider the test pipe before taking the cat out.

 

Well the emissions are killer here in Jersey, but its stock stuff now and I'm gonna get it to pass first, I'll have a 2 year sticker than, after that passes, its all modding from there. I'm probably gonna do 4-2-1, with no cat 2.25 pipe all the way back to a nice muffler of some kind, anyone recommend a nice sounding one? Also, the motor I decided is a B16

 

Any other opinions??