Yep you can use a better radio. As a matter of fact, I just got my CP Pro set up on a DX7 (that I bought for a trex) today and flew it for the first time. Since the RX that came with it is being used already, I bought an AR6100 RX and put that in the CPP. So far it seems to work very very well. It's just a matter of tweaking it but I'm very pleased with the stability of it in a hover (it's too nasty to go outside and really push it).

Good luck.