You don't have to run a low pitch prop on a 4 stroker. In fact I run a 13x6 on my Saito 72 and it still has enough power to hover a 5lb plane. If you have to worry about your engine dying at lower rpms then you need to adjust the carb better and if your bogging down the engine then you've over propped it. A perfect example of this is all the guys the use the APC 12.25x3.75 props on a 40 size 2 stroker. That's over propping and it will bog down the engine because a 40 size 2 cycle isn't meant to swing a 12" prop. Remember the largest diameter, lowest pitch prop you can swing on an engine does NOT make it the best prop to use for 3D.

As for comparing a $300 2 stroke with a $300 4 stroke I highly doubt your comparing same size engines. Were talking Saito 100,120 or similar for a $300 4 stroker and I don't know of any 2 strokers in the equivalent size of 90-120 that cost $300. Maybe $225-230 but not $300.