I was thinking 2 motors would be unreal torque, resulting in potent accelleration, and punch.

However it could slightly hinder the final top speed.. very slightly, I say this as even 2 identical labeled motors will not have identical performance, and one motor may cause a load/restriction on the other.. just my thoughts.

I'd prolly go the dual motor path tho, because if you're building something for top end, you want it to get to that speed as quick as possible.