RE: Lipo Pack for Transmitter ?
Welll that depends......
On some systems the raw battery voltage is used to power the RF Amplifier and all the logic circuits are driven from a regulated 5V line. This means that the regulator was dropping 4.6V nominal but now is having to drop 6.1V. This extra voltage is converted into heat, so if the manufacturer skimped on the regulator then this additional heat could cause the regulator to fail prematurely.
On other systems ( Spektrum & JR 2.4 GHz), the RF section is run from a regulated 3.3 V line. [X(] So now this reg has to drop 7.8 V instead of 6.3V, the logic regulator is still as above.
So basically, if the designers put in decent regulators capable of handling excess voltage, it should be okay