you cant draw more volts, voltage is whatever your pack is. I think the point is that higher kv motors will draw more current.
Theres no strict rules really, it wont explode if you plug in a 3s pack with a 5000kv motor, but its probably no good on the warranty side of things, and will likely thermal easily.
That said I've succesfully run 8th scale buggy conversions with a sidewinder and a feigao 8L (~3000kv) on 3s and 4s A123 packs (up to 14.4V) without any temp problems. Its all about gearing really.
The medusa you mentioned would be great with the sidewinder...
I also want to vouch for the medusa. I have run the medusa 3300 as well as a Neu 1509/1Y (3600kv) with absolutly no problems. Actually it ran cooler than my MM... Go Figure