custom exhaust..how much?performance?
 

Well i have a BOMZ GT-spec muffler, and im planning to take that to a local muffler shop and get it custom piped from the cat with 2.5 to the muffler. how much do you guys think it'll cost me? and are there any real gains with this setup? who here have also got there exhaust custom made?

you'll definately feel a nice gain.
However you have to think about your 6 ports. (you profile says SE S4)
They need the exhaust backpressure to open. You can find a way around it tho.

Also it'll be crazy loud.

i paid about 350 for a custom setup...2.5 ypipe to 3inch mufflers (straight through mufflers), although i dont have any hp gains, it was a huge performance increase but keep in mind i took my cats off long ago. with the stock cats the gains will not be all that great and maybe a bit dissapointing but a high flow cat or a cat replacment pipe would really show the gains of the catback.

Oh my bad I thought you were talking about a full exhaust.
Catback only you will get maybe 5hp.
I got my 2 2.5" Magnaflow mufflers installed for $180, including the mufflers.

my zost setup = custom header, custom piping, back to GOOD stock mufflers. 40 hp gain or so.
w/o header: about 25 hp gain.

i got mine done for $80...... 3" cat back and install muffler...... single exhaust...... it shouldnt cost anymore that $150... (for single exhaust)... and $200-250 for dual

It depends on whether you want to go with crush-bent piping or mandrel-bent. Mandrel-bent flows a lot better, but it costs a lot more.

i have a similar question, if i got the RB header and presilencer but did a custom setup from there back, would there be enough back pressure to open the aux ports?