I used to dream of having a 700+ RWH. Not anymore. We are talking about a 3.0L engine pumping high HP numbers ONLY b/c of a large turbo. Large turbo = lots of lag = not fun to drive on the street. Those high HP numbers will be found after 5500 RPM. How often do you plan to be at 5500+ RPM?
If you ONLY plan to race your car, maybe go with high HP. If ANY kind of street driving/racing, stick with the 'smaller' aftermarket turbos. The car will be much more fun to drive.