I have a 1999 civic coupe with an apexi N1 cat back that im about to take off and replace with a new cat-back. My girlfriend has a 2001 civic coupe, i was wonder would it be possible to take the piping from my old N1 cat back and modify it to fit under her car and be welded up to her stock muffler. The reason why i want to just run my piping to her stock muffler is because she does really want a big after market muffler be it that her car looks totaly stock she just wants a little performance gain which i would expect she would get but probally also create some back pressure at the stock muffler. Can anyone give me some insight on my idea?

 

Not at all worth it. If you're going to flow through a stock muffler, don't kill her with resonance from large piping.