Depending on the gearing you may not want motor speed over 30k rpm, as the gas engines cannot turn much more than 15-17k rpm. So unless the gearing is way lower, high rpm motors will not work well. On the baja project, I had figured a 700kv motor on 10s lipo would work for stock speeds with a 12t pinion, 5 teeth less than the stock gas engine pinion... That was around 28k rpm...
HW makes speed passion, venom, and orion(not 100% sure on orion so don't quote me on that).
The mouth does look majorly restricting and is it just me or does that look like a plastic pinion? The plastic spur is nice as it'll keep the noise down a lot(I hate the sound of metal to metal meshing)