Which would provide the best initial bump in power:

A - Stock exhaust with hi-flow cats

or

B - Stock upper pipes with catback exhaust.

I'm not interested in loudness at all, something deep and quiet, thinking the HKS HiPower or maybe the Greddy Evol... but I'd rather just do a minimal muffler swap with stock exhaust and hi flow cats to help keep it quieter...

Opinions?

 

Most power for the $$ would be a custom exhaust setup.

It'll likely be much cheaper than the Stllen HFC or any of the catbacks you'll find online.

I'd bet you could get HFC's, new mufflers, and new piping all done for around $600.

 

Replace the stock y pipe with a custom h or x pipe. The stock y pipe is very restrictive. This will give you a nice power gain but still retain quiet sound levels and can be done for about $125 by any exhaust shop

 

I had the same question as well and in my understanding, muffler did not give any more HP? Just cool sound factor?

I love how the stock G35 sounded already, but just interested to buy the part that actually give "horse power" not the whole chabang.

 

What is it with all the noobs asking the same questions over and over when they could be answered with a VERY simple search?

 

custom is the way to go...

 

i've been searching for months... but there doesn't seem to be a lot of custom exhaust jobs out there. a couple swaps here and there and some sound great and some sound like crap. I'm not asking what's the best exhaust or best this or that, I'm asking for proven power gains based on different mods... There's a huge long thread about the FI exhaust and the addition of HFCs and the tests with the stock vs. FI exhaust, but doesn't show gains from the FI / No HFC to FI / HFC.... I haven't been able to find much testing on HFCs alone. Not saying they're not there, but I haven't been able to find much of anything on that.

If you can find some, I'll be glad to read them. thanks for your helpful and informative response....

 

I just read in another thread that someone gained some power with just HFC's. It's one of the other exhaust threads in tech.

 

N2O is the cheapest hp per $. Just get two of the big bottles....by tonight.