asianspeed

I'm about to install my turbo and I'm wondering about the exhaust pipe size. right now I've got a 2.5" pipe that I was going to use which will weld to a 2.5" e-cutout, I'd estimate the cutout to be about 2 feet down from the turbo. I know everyone likes to use a 3" exhaust pipe, but will my 2.5" pipe with the cutout be enough to support 250-350 hp? Also, will backpressure be an issue?

Thanks