Considering that David Fitzgerald runs a PA75 in his Thundergazer, which is smaller than the Legacy, a PA61 on pipe is not too much engine. Controllable power, not horsepower, is the goal.
My own Legacy is E-powered, but I have a Brodak Legacy kit (unbuilt) and a PA61 on pipe that will go into it. Here in California the larger PAs are more popular, especially the PA65 if you can get your hands on one.