Get an ESC with a fan, a 4.5 or hotter motor will generate plenty of heat. I have to vouch for Novak for running Mod TC if chassis space isn't an issue, they seem to have the best brakes, but brakes generate lots of heat as well (the energy has to go somewhere, your ESC and motor have to take it). I run two fans on the motor and one on the ESC, both come off cold after a full pack.
I race toy cars for fun. If I need to explain, you'll never understand.
If everything is under control... go faster.
WTB: Carpet racing in Arizona.
It is obvious and intuitive to the most casual of observers that RC racing is better than golf.