What exhaust system? / Year of car? When I searched i came up with:
1992-1998 Civic ex two and four door are the same length for DC , 99-00 coupe/sedan are different.
Im guessing that adding a little length may be necessary after the cat.
Because the LX and DX have the cat right on the exhust manifold and not under the car after the axle seats. If you have an EX it will line up and your won't have to do anything. Trust me i have a 96 LX and put a full 00 EX exhust from header back and everything was cool
umm....ur story made about 0 sense to me....he has a b16 swap; b16's dont have cats in header. I sold the kid the exhaust and i remember him comming back and bitching cause it was for a si, and that it didnt line up