Which Lehner

I'm working on a buggy conversion and have already bought a Feigao 7XL. The thing is that I just came into some disposable money and would like to get into a better motor. Since I think that 4S lipo should be enough for a buggy on a track, I'll likely be running a Mamba Max controller, I figure that a two pole motor would be the best way to go. I'd like to get into a Lehner.

I'm figuring about a 2200kv motor, so which would better serve my purpose, a 1930 9, or a 1940 7?

Considerations are heat and runtime.