I received my COBB AccessPort with mail order Willall tune a few days ago. After a simple 20 minute installation process, I was on my way. The car feels stupidly fast on the street now! It seems to come on boost harder now and the acceleration is laugh out loud fun.
As I have only driven on the street at this point, it is hard to give too much valuable insight into the cars performance after the COBB tune. I can say it feels significantly faster and seems to be terrific bang for buck value. I am booked in for a track day this coming weekend so I will report back after that. If I get the opportunity, I will run the car on a dyno at some point.
Also, I think it is probably just my imagination, but the transmission seems to shift a bit smoother. I can't say this is definitely the case.