Does your friend race or go to any tracks? If so I would say yeah just go with the Spektrum and pick up a few receivers. That would cost quite a bit though. I ran the flysky gt3b for awhile because I had the same problem. Waaaay to many vehicles and was tired of swapping receivers all the time. The radio is only like $40 and receivers are $7. It has all the adjustments just like any high end radio. I wouldn't suggest using it at any tracks though,supposedly they mess up Spektrum radios. Go figure.
http://www.hobbypartz.com/79p-gt3b-c...FVFgfgodF3oAxQ