Forgive me if you've already gone to 305Vdub, but I got GTI a few weeks ago and I took the car to them to get a Unitronic Stage1+ tune. The experience was awesome. So awesome, that 305vdub made their own cat less downpipe that I'll be getting this week, along with the Unitronic Stage 2 update. They even mentioned to me that they have a custom cat back system in the works with a resonator and muffler. Looking forward to it when its done.