Originally Posted by Northern Mike

Looking at your motor/ESC options, I will say the first two options will be tough to hit your desired speeds without risk of burning either the motor or ESC. I had a leopard motor almost exactly the same as the first option with a 60A ESC. The motor is not a 540 motor. Its closer to a 380 with the can size (including cooling fins) of a 540. I popped my motor doing a speed run on hard packed snow at a speed of 55kmph. Had been OK as long as I had snow coating the motor, but that one day I didn't and it died.
Your second option sounds better, but will be still tough to balance the tempature and gearing. I have also noticed that you can get a decent Castle Creations combo for about the same price as that combo. I'm not promoting the CC systems, but I know its all the 100mph guys talk about.
From what I can see (and others may confirm or prove me wrong), lower kV numbers, the higher the power. More power, the faster you can get. The sweet spot appears to be 2500kv to 3500kv. KV is the motor rpm per volt applied. The word I've heard is 40, 000rpm is about the point where heating becomes an issue.

Myself personally, I'm running a 2930kv 4pole motor. Its estimated at 65A and good for 5s (18.5v). My target is 60mph on snow, which may or may not be obtainable, but its my target. I've only been able to hit just under 60kmph on a 2s.