Basically, you need to run an external BEC and disable the onboard BEC (unplug the red wire from the RX plug). Then it would be a good idea to run some capacitors (about 35V ones will be fine).
Others will know more than me I'm sure, but I'd suggest looking at
this forum to see what people have done to mod Tekin R1 ESCs and Castle Mamba Max ESCs to take a higher voltage. In fact, if you haven't yet got the LRP ESC, I'd run one of these instead, an MM will be cheaper, and can probably take higher voltages (some have run these on 6S, Adam was only running 4S if I remember correctly).