ive never used a voltage regulator, and have never had a reciever fail on me. A good few servos, but never a reciever. I use a hitec feather and theyll happily take a fully charged 2 cell li-po. The GWS park HPF X servos cannot really handle 8.4v. I used them for drive (speed hacked) and on a flipper, and have lost about 3 of them in 5 events.

If i ever build ants again, ill defo be regulating them to 5v.