I've just got a GTI TURBO and did a 60 mile trip (A road and about 17 miles of Motorway). Was a boring drive as i was trying to see how high i could get the MPG. I managed 40.1 which im well chuffed with!!
Most of the time im around 35-37 though.
Get the GT TDI if you want performance and Economy, but expect to pay more for it!