Pharoah:
I have the pitts & I am running a g-62 in it, you should be able to use the Q-52 without too many problems. I know some people with the us-41 in their plane & are kind of dissapointed in the performance. The us-41 looks to barely get the plane off the ground. As far as mods go you should pin & fiberglass the engine box & do the top wing mods as suggested by great planes.
Good Luck
Gil "rcismylife"