It had better have some padded bumpers or a really low acceleration/max speed because I'm pretty sure I know what's going to happen to the throttle...
There are 1/8'th scale RC cars which are scary and go at some extreme speeds. They also guzzle gas or chew through a battery pack in a matter of minutes. To get the required power, electric ones tend to use 20V+ battery packs. NiMH/NiCD for entry level stuff, and Lithium Poly at the high end. I'd wager that you won't need that much power and can probably do with a higher gear ratio/lower voltage.