Ok, so I got some great runs in last night with the rebuilt center diff and 16/48 gearing. Temps were well within reason... 158F for the motor, 127F for the esc, and 122F on the batteries after a 10 minute run at the park. Everything is great, except for the drop in top speed. Its still seemed to have enough for a med sized track, but kinda lacking for a large soccer field
I'm very tempted to get a better set-up, but with the MMM just on the horizon, this set-up will stay for a while.