The ball drive is a bit fragile if you run it too fast, Erb has some excellent articles out there on improving the oil supply.
A turbo is "free" (no actual power take-off), except for the power lost by less-than-ideal chamber evacuation on overlap (normally aspirated engines do fairly well, race engines very well, blowers completely remove all exhaust, turbos always retain some). The normal pressure ratio for streetable turbos is intake boost × 2 for backpressure: 10 psi makes 20 psi in the exhaust manifold. It can be reduced, but getting it down anywhere near boost is a lot of work. Pumping the cylinder out against 20 psi of resistance is extra work.
A 300" engine at 8:1 CR actually has 343" of possible mixture because the chamber is also full at ignition. It's not added to the official displacement because it's generally not "clean" mixture, but contains lots of exhaust gas (and of course, it means that the engine size changes when you change the CR - which it does). With a blower, the chamber volume burns also.
