I cant justify spending 1200 for one of the bolt on kits just for 9-10 hp. $110/hp is crazy. But i really want an exhaust. I talked to a friend of mine whos uncle works for GM, and has is own race team. I was curious to know if going with a 2.5" system is needed on these vehicles? He has a mandrel machine, and said he could make me a custom exhaust, true dual, custom x pipe, twin resonators with dual polished stainless muffs, either borla or magnaflow for 400-450. I said that the stock 2.25 should be enough since it is a true dual system, the race team owner said upgrading to 2.5" would benefit on a high revving engine such as the VQ. I was worried about increased resonance with the 2.5, but he said that the resonators would help reduce that occuring. Should i just stick with the stock 2.25, and just upgrade to high flow resonators and polished mufflers, which could be done for about 300? Or should i spend the little extra for new larger piping. I dont plan on modding any internals of the engine. Im sticking with the warranty on this one haha. Intake and exhaust is really as far as i plan on going for a long time.

 

Go with 2.5 inch, youll get better gains from more flow. FYI, Fast Intentions uses 2.5 inches for their exhausts

 

EnviedG35: The stock exhaust isn't 2.25 all the way through. There are several places that it necks down to less than 2". If you're gonna try for 2.5" on your sedan, let us know how it sounds.

chilibowl: FI uses 2.5 on the coupe exhaust. They actiually use 2.25 on their sedan exhaust to reduce the drone which seems to work.

 

if you're worried about 2.5" resonating, they make this nifty thing you can add into the mix called a resonator

example: my fujitsubo power getter on my sti was 3.18", flaring out to 3.5" ID at the axleback. it was quiet and never droned because it also had 2 large resonators.

2.5" piping is nothing.

edit for clarity: it's nothing soundwise

 

Alright thanks guys. The price he gave me of $4-450 includes twin resonators, x pipe, 2.5" mandrel bent piping, and twin polished magnaflow or borla muffs and tips. I'll def post some pics and vids as soon as i get it all done.

 

you should go with 2.25 piping...

 

I think im going to stick with the 2.25 piping. I really dont want the drone like my previous car and im still going to use resonators.