Some people tell me that I shouldn't replace certain parts of the stock exhaust system because if I free flow-it all I will just lose backpressure and because of this I'll lose Horsepower. Others tell me that the better the free flow the better the HP gain. What's the real deal? What certain parts of the exhaust should I change then If I shouldn't change it all?

I already installed a straight (test) pipe that replaces the catalityc converter. Is this slowing me down? Should I put tha cc back again? I'm also waiting for the Y-pipe to arrive. I already ordered it.

So what should I do to increase HP to the most?

 

Back pressure is bad, to increase HP you should get a hi-flow cat, 2.5" catback and ypipe which would get rid of the pre-cats that are restricting air flow.

From the 4th Gen FAQ...

 

So then should I take off the straight pipe and put the catalytic converter back again or should I leave the straight pipe ? Right now I'm not sure if I'm going to be able to buy a high flow cat...

 

Leave the straight pipe in. That will give you more freeflow.. Too freeflowing and you will backfire like me

 

from what i heard, i belive that your motor needs back presure or it will run bad or somthing. Not sure the real problem it may cause, but hp gains for more free flow are alot. And if you put that y-pipe in, have a straight pipe then you have little back pressure, only thing giving back pressure might be the resonator in the b-pipe. Just my 2 cents.

I may be wrong.. I'm Not a pro at machnic stuff