you can keep the High compression. run about 5 psi boost with a To4E and get a boost retard ignition system. with the right set up you should get at least 300 HP without going into the engine.
more HP with some good tuning.

I built a customers VW Jetta turbo with the 16V 2.0L engine with 10.8 to 1 compression. I installed a Crane HI-6 with boost retard.
the timing under boost was 25 degrees. the car made 320 HP on the dyno with 5 psi of boost! (TO4E hybrid)

A lot of the Honda turbos are running over 10 to 1 compression and making over 400 HP. so y not a benz motor?