Whether you are going to have overheating issues or not, is going to depend on what you consider to be overheating issues. It's also going to depend on the climate where you are, the weight of your vehicle, and your driving style. The motor that you get will have an impact too.

For the coolest running, I'd go with the 9XL. In a racing environment, I had to go to great lengths to be able to run for 30 minutes, and even then the motor is at or over 200*F. In any case, the motor overheats before the battery needs charging.

If I try to, I can overheat my 9XL in my sub 10lb truggy in about 6 minutes. The Feigaos are just to inefficient to be able to avoid the heat.

I'm sure that others will have a different opinion, as I've heard of others running their Feigaos and only getting temps of around 160*F, although I don't understand how.

If you really want to be able to run without heat issues, you're going to have to go with either a Lehner or Neu motor and compatible controller.