I have 2 Blasts. Mine are both brushed motors. You can get some performance by replacing the stock prop and shaft.
I was told on the Traxxas site that this boat did not handle well enough for the speeds brushless would produce. True or not i do not know but i am happy with mine with stock motors.
You can also get slightly hotter brushed motors. All IMO; Don
P.S. check out the Traxxas site. They have a section on the Blast.