Everyone has input on battery charging, just telling you what I do and what I have seen. If you plan to make the A main at any major race, you are discharging and charging like this in the US. As for the higher voltage, the newer lipo cells were designed for this and it is safe. Not legal at a Roar race but what is done at clubs that do not have voltage rules. Not saying everyone should follow this advice.

If you charge at 1c and make sure to store your lipo at the correct voltage, you should can probably get years out of a pack.