These radios are such a small draw heat is not an issue, and about the voltage fresh good AAs will be well over 6 volts. If your really worried about the extra voltage hurting something just use a 5 cell flat RX pack.
The reason we want to use other types of batts is because we allready have them and they are rechargable.
No one can argue a 1700mah pack is going to last longer and be cheaper in the long run than AAs.

I doubt horizon would warentee my radio anyways, The wheel isnt stock, the trigger has been melted and good lord like every hobby product ive ever owned I took It apart.

LOL Hi-voltage servos, All Good servos run fine on 2s lipo