The biggest difference between allowing the 1.8T VW and the new WRX, besides 77 hp stock, comes down to one word - TRACTION.
Yes, you can get 200 hp out of the VW, but it's FWD w/o a LSD. More power just means you spin the inside tire more.
The OneWD aspect is what limits the BMW 3-series. It is faster straight line than just about any car in the class, but when you have to apply power in a turn, it's limited. That's one of the things that allows the Impreza to beat cars that are 1-2 sec faster 0-60 (I know it's not the only reason, so no flames).
'90 Mazda Protege LX