Just a quick question:

Assuming that all y-pipes are close enough in sound... how much louder do these make the 4gens? I'm generally not a fan of loud *** exhausts (i generally prefer it quiet most of the time), but I do enjoy the sound my intake (hacked airbox) makes at WOT. How much louder is a y-pipe at idle? at 1500-2000 rpms? at WOT?

 

can't really explain how much louder it is. But i will tell you that it is not louder than your hacked airbox.

 

do you plan on getting a full exhaust or just have the intake and y-pipe? If you do that, I am pretty sure it won't be too loud...I had a full exhaust put on all at once...so I couldn't tell you for sure...full meaning y-pipe back

 

a y-pipe won't drastically affect the sound of your car... you'll notice a difference, mostly between 1-3K rpm... a quiet hissing sound maybe.

different people get different results from different pipes, so it's hard to give you an exact answer here.

after 3k RPM, it's all intake... just like before the pipe, so don't worry about that.