If you are new to all this (i'm relatively new myself), your best bet and simplest install by far will be to install an off-the-shelf turbo kit (Star or HRC). If you go this route, the downpipe will be setup for 2.5" exhaust so unless you plan on fabricating a 3" downpipe from the turbo to your 3" catback exhaust, you probably won't see much benefit from getting a 3" catback. It's also more of a challenge to route the thicker 3" piping (may not be able to go above the rear axle).