JMP Starfire IIa and IIb are the same except for the size of the ailerons and flaps. On the IIa they are close in size on the IIb the flaps are larger than the ailerons.
JMP IIc is an all composite version. the wing was more straight and with more span but is thinner. Had bulges in top skin for tire clearance

The Yellow Aircraft Starfire is very similar to the IIb. It has an added hatch at the canopy.

I have flown the IIa, IIb and the YA version. They all fly the same. The ones with the larger flaps are easier to land.

Hope this helps