I'd say your temps were a little high. I have a 13+lb Flux using that same motor and the HPI branded esc and when running 6S I don't see temps anywhere close to yours. My lipos get just warm enough to know they've been used and the esc fan doesn't run, meaning temp is below 150F. Motor is warmer than lipo, but not hot. And temps here are in the upper 90s. Your temps say you're overgeared.

http://www.rc-monster.com/forum/showthread.php?t=2200


What do you have your lvc set for? You'll get better life from your lipos if you run a higher lvc, like 3.5v/cell and don't run to lvc. Its not good for lipo life if you're using more than 80% of their capacity (4000mah in this case).