exhaust setup - 3" or 2.5"?

[Shane@DBPerformance]

You aren't going to see much for gains going from a 2.5" to 3" exhaust with your turbo.

The 3" exhaust could cause boost creep, because it will flow the exhaust easier. With more flow, the wastegate portion might not be able to keep up and it could be easier for some of the exhaust to go through the turbine wheel, instead of out the wastegate, causing it to make more boost. You will probably lose some part throttle, low load torque feel, when you goto the bigger exhaust. At WOT, it should gain a little torque, spoolup and an HP, but when you take off slowly from a stoplight, it might feel a slight bit weaker.

Stainless steel is good at keeping heat in, which is what you want with an exhaust. Most of the cheaper steel exhaust also have some sort of coating on them though to prevent rust and help keep heat in. Stainless exhausts are usually a tad bit lighter than cheaper normal steel exhausts.