A couple of years ago I ran in a 1000 lap race together with Jilles Groskamp, Markus Möbers and Peter Meurs. We ran a 15 turn motor and only had to change it once (after about 700 laps one of the brushes came unsoldered). Nowadays I would probably run about the same wind but then use a V2 style motor with endurance brushes so we could do the whole distance with one motor, or alternatively run a brushless. Make sure the motor is not too fast. It is all about consistency.
As to the batteries, you should look into building quick battery change system. We managed battery swaps in about 4-5 seconds with one super stop that only lost us 3.5 seconds on the track! We averaged about 10-11 minutes for each pack. Moreover Jilles did the fastest lap while running our last battery