What throttle profile are you running? Most are running TP2 (27% timing advance). Also, if it's slow and still getting hot you may be under geared. I'd take it to the track, run it for 5 minutes and temp it. Re charge the battery and gear it up, run it for 5 minutes again and compare the temp to the old gearing. 5 minutes should be enough to show you which direction you're going without endangering your motor.

Also, is the motor new? Over time the rotor will loose it's power. Temps will climb and performance will drop, This will happen faster the hotter the motor is run.

I run the 1700kv and don't need any more power. I'm about as fast as any nitro down the straights and can have more grunt off the turns/jumps. I come off the track ~150f after 15 minutes.