Sadly, on my system at least, I can confirm that the cub is a framerate hog. There are models that are, and models that aren't. It does not seem to relate to level of detail or sophistication.
o Realair Scout Package, Spitfire.
o Anything Carenado
o Lotus Albatross
o Just Flight Tigermoth
o Digital aviation Katana
I have most of the listed add-ons, and for my case I dare say the Cub certainly belongs to the "Good framerates" category, on par with those listed above.