300hp with a turbo 4 is no big deal.
Look at the SR20DET or the B20. People make 300hp with a T28 and bolt ons.
Honestly, VW tuning is probably one of the most expensive routes, as far as $/hp.
Youve got the VR6, which is ok from the factory, but with bolt-ons, it doesnt do much. You either need to turbo, or supercharge it, and you still have the torque steer issue.
Then you have the 1.8T, and its pretty weak from the factory, and its maxed out at 310hp(APR Stage III)
The base cars are $$ too. Not like a Honda or a Nissan where you can buy a shitty car and slap a turbine on.
If you want AWD, you gotta go Audi and quattro and luxury features make it heavy as fawk.
All in all, VWs are pretty much show oriented unless your talking turbo VR6s, Golf R32 or the Corrado