Originally Posted by TryHard

Personally, I don't feel the fan contributes much, if anything to the cooling. Does make a cool noise though. I'd wager that the majority of the cool running comes from the materials and general quality build of the motor. If you have one in your hands and compare it to other brands, you'll understand what I mean.
Also, I also have a 21.5t that I use in my F1, and compared to the D3.5 I used before it's faster, and runs cooler.. After 15min, was still running at around 60C, whereas the D3.5 would have been up in the 80's.

As for spares. Tuning rotors and sensor boards are out there, but maybe not yet advertised. The manual in the box details all the part numbers, and there are around 10 different tuning rotors to chose from. 12.5, 13.0, 13.5, with 5 or 7mm inner cores, and with or without fans.
Regards
Ed