New JR and Hitec HV servos. How to maximize their potential?

[Ryu James]

So JR came out with their new HV $200 servos a few weeks back and now Hitec has been advertising for their HV servos with titanium gears. stats on both servos are astonishing. 480 in/oz torque! anyway, the ads i have seen say that this is only possible with 2s lipo, or 7.4v input. i have also seen ads that say in small print something to the effect of "in order to generate this high output you need to have your system setup accordingly." i am wondering if anyone out there knows how to do this?

i run 1/8 brushless buggies and truggies on 4s or 5s setup with a standard spektrum reciever. can anyone tell me how many volts the spektrum sends to the servo? is it adjustable? would these new 7.4v HV servos be useable with my setup or should i just buy a standard high torque servo that lists the 4.8/6.0v stats? just looking for a better understanding of all this.