So I'm planning out doing exhaust on my g. I need to put new catalytic converter because I believe I have hole in there , I hear this farting sound right under driver seat and also when it used to be cold couple weeks ago I saw it was "leaking" in that area. After I put new catalytic converter I'm not sure whats next. I was thinking about 2.5" piping and I dont know if thats good or I can go bigger , notice I'm not planning turbo in any near future. For a muffler I want MagnaFlow but i dont know if I should go oval or round and how big , I want nice deep sound but not a fart can.... and last what are pros/cons of eclipse 1g non-turbo headers?