Hi Barkley,
Which of the motors are you talking about, or is it both
10-15 mins is actually a fair bit of life for the intended use. ie 1 track day or for the odd couple of seconds burst on the road
Don't forget this has a similar effect to NOs in that you are chucking more O2 into the cylinder so you need to overfuel at the same time. The simple way to do this is to have the switch either under the pedal or on the throttle linkage so it only activates in full throttle applications.
There are brushless motors available as well but I havn't a clue, Can you see any or do you know of any other moors that would be suitable?
If it ain't broke, take it apart and see how it works