Your Sting-Ray was intended for power levels between zero and maybe 200W. It was built to be cheap above all other factors. It puts your body in a position that makes it difficult to cope with bumps, quick maneuvers, and road hazards.
While it's a good idea to have rear drive on a bike that's so heavily rear weight biased, it's probably not a good idea to turn up the power or speed above what you already have. Is your bike the kid sized version, or the "Spoiler" adult sized one?
Figure out what you'll do to have an effective rear brake (other than regen braking, which can leave you mysteriously without brakes at inopportune times).