I'm sort of in the same spot as you are. I'm setting up a HV Muggy for about 35-40mph. From the beginning I was having a lot of temperature issues caused by high amp draws. I switched from a 80mm medusa to a Neu 1521, and still had temp issues and high amp draws. The Muggy would still fly though. I even test ran a 60mm medusa in the Muggy, and it would still fly. Like someone stated beore, these brushless motors will do about anything. They'll just pull as must amps as they need and are supplied. Small motors will heat up with these amp draws and larger motors will stay cooler.

I rebuilt my diffs a few times to check for any binding issues. I didn't find any issues with them at all. It took me a few months untill recently I found a setscrew was missing in the rear right cvd. The pin in the cvd had come out and was causing some serious binding. Now the cvd is bent and useless. I'm waiting for some new cvds to see if my problems are resolved.

I was told in this forum a few times I probably had binding issues. Just took me a while to find them.

Also, I found the eagletree datalogger was a big help. really lets you know whats going on in your setup. Probably a better investment than getting the RX8. I have recorded a high of 4000watts (geared for 40mph and with binding in the drivetrain).