The Cheetah Cub uses factory sized head and intakes, it was designed so that people could use most of the parts they already had. It doesn't have powervalves
The Cheetah cylinder uses larger reed cages and a largrer head. It's usually larger bore size than the cub. It is available with powervalves
The Cheetah DM cyl uses even larger intakes and usually a larger bore than the Cheetah
As for the piston windows, that is usually a builders option. there are some that say the window size doesn't matter and some that do. Personally i like to open up the windows a little.