That's not too bad for that motor/battery setup. If you're not running on a really wide open track, try going with a 11T or 12T pinion which should get you down to the 35-39 MPH range. It might reduce temps (but it might not also). It's worth trying if you're trying to reduce temps. You can't really ask for a super cool running motor if you're running 2650KV.

EDIT: I also wanted to add that running mech brakes should reduce temps a bit also and if you're running the Tekno kit, you don't need a radio that has channel mixing. All you need is Y-harness so that you can plug the ESC and brake servo on the same channel. Mechanically, you can configure the brake linkage to apply brakes when the servo pushes instead of when it pulls. When you're pulling the throttle, the brake linkage will move but basically wouldn't be doing anything.