I don't think you have to build your own controller any more
check this out - I've been drooling about it for a while
EMP/Stewart Components E558AR - EMP Stewart Electric Water Pumps - summitracing.com
55GPH - 10,000 hrs estimated life - 8 amps - inline and small
I'm guessing with the box on the side & the reliability expected, the motor is brushless
only thing holding me back is the price