Generally not a need for a high Voltage servo for most electrics, they are a Nitro thing for lipo receiver packs. Usually you can get pretty high levels of performance out of a standard Voltage servo without the added complexity of a high Voltage electric set up.

But if you must, it depends on what Voltage your main battery pack is, and what receiver you have, whether or not it can handle the higher Voltage. Post your battery Voltage or cells and receiver brand/model and we can help.