semi-custom exhaust + cat questions

[Rennat]

So after seeing the ebay s13 dual cat-backs, im deciding if i buy one, the cost of one is pretty in expensive even if i have to go the exhaust shop to get a new mid pipe for it, but i have to have a cat in there. so heres my ideas:

Single 3'' in/out cat after the downpipe
OR
dual 2.5'' in/out cat on both of the pipes after the y split. i would weld them in where the pre muffler goes

im more concerned with smog then i am with noise. if a single 3'' will do a better job tha dual 2.5'' then id rather do that, i would like to hear some ideas and theorys.

 

[Poodles]

as you know, the duel setup would be more expensive, but personally I'd use a bolt on 3" high flow cat and get the rest of the system made to fit to it.

Not having any flanges makes removing the exhaust a ROYAL pain...

 

[Rennat]

the y-pipe is a 3'' in and dual 2.5'' out, and the inlet has a flange on it... so that would be extended to meet up with my downpipe flange thats on my downpipe... i'll NEVER have a once piece exhaust again... biggest mistake i ever made on my last car.

if i can buy my friends 3'' cat from him then i'll just do that. haha



dual muffler=========dual 2.5'' cat==>dual 2.5 to 3'' FLANGE//FLANGE downpipe up to turbo

thats would it would look like or...

dual muffler========dual 2.5'' ypipe to 3'' cat FLANGE//FLANGE downpipe up to turbo


and as long as i keep this all under $400 i'll be happy... the exhaust is like 210shipped, a NEW 3'' cat is like 60shipped (dual 2.5'' are like 120ish), and i could get a flange local for under $20... so in all im looking at under 300-375, which for a dual 2.5'' setup is REALLy nice.

 

[bmoss85]

i thought about doing a 3.5" cat back to a y and dual 2.5" mufflers. i really am starting to like the of the dual mufflers.