For a 50cc plane for Intermediate I would go with the Aeroworks or EF Extra's. Edge's are good at IMAC but are better at 3D

Now IMAC is all about knowing how to setup your plane properly and fly the sequence properly and any IMAC legal plane can do well if properly setup and flown.

I am sorry but if you are asking about a 50cc plane for Intermediate I have to ask if you have experience in IMAC already. If not I would start out in a lower class, even if you can fly the Intermediate sequence until you get the proper expereince. You cannot move backwards, jsut forwards in IMAC.

If you have the expereince thwen please accept my apologies