hey im building a new set up for my built Z6 and i am wondering is it worth to tun a 3'' down pipe. I have a 5 bolt exhaust on my garret and the flange accepts 2.5 pipe. Can i get away with a 2.5'' downpipe for 300hp? What do you guys run?

 

Just do a 3'' and leave it open .. 2'' are for pussies

 

Do a 2.5 all ther way back with a good flowing muffler (magnaflow turbo, vibrant, etc...)an E-cutout to open up the DP when you race. 3" is to dam loud, and even louder when you have no cat. My buddy put down 320 whp w/ a vitara/ turbonetics setup with 2.5 all the way back, and that was with no cut-out.