Probably not. There's not much room behind the engine to clear the Pitts style without carving away a lot of the engine box.

I am using a G-38 with a rear mounted J'TEK muffler and I have to cut a chunk out of the box.

For a G-45 with a side mounted exhaust outlet, any of the "cannister" mufflers will work. Not the 3-D type of canister, I'm talking about the type that come with a lot of engines, black sheet metal with one or 2 outlet pipes. There's lots of roonm on the sides of the engine, but none at the back.

Maybe a J'TEK or Bennett muffler, as long as it only sits on the side of the engine, not the rear.