thanks for the info goosef22.

I already have the HS-645's so I'll have to stick with those and see how it goes.

As for the dual batteries I didn't realise you could plug the battery into any old slot on the receiver, I'll definately run dual batteries/regulators/switches now for safety. With a dual battery setup like that I assume that power is drawn equally from each battery?

I've been reading about the A123 batteries and they do look promising but the batteries are rated at 6.6v. I thought recievers/servos could only take a maximum of 6V? If you don't use regulators won't you be overloading the receiver/servos?