ok so im stuck between the top speed non-res system, the cobra sport non-res system, or possibly going with a straight pipe, my only fear is ill go with straight pipe and it will be raspy as hell and I don't want to sound like a civic with a 40 dollar canister, so my question is whats the best diameter for a straight pipe? I was thinking 3" but would that still be to raspy? or does less space in the pipe=more rasp? thanks. also, whats the best size for good back pressure and such.

 

this is my 06, on non-res test pipes, y-pipe, and 3" hks... only resonator is the muffler.

 

I have a Nismo intake, Nismo headers, and a full Nismo s-tune exhaust that i just did a muffler delete on, and I hate it.
I did a 2.5" y pipe from the resontator with stock looking tips.
It was buzzy before and now it drones like crazy too.
Granted it sounds amazing at WOT, But driving around town, it shakes the whole inside....moral of the story, straight pipe sucks...lol, plus i feel torque loss...