I made one of those 5 buck boost controllers. It worked really well for me. You just need to know how tight you need to make the spring. I had mine too tight once and I went for a test drive. I watched the boost guage spike to 12 pounds! Scared the hell out of me. Fortunately, nothing was wrong with the motor.
It has to be the best bang-for-the-buck mod you can do!
$5 = 25 whp!
good luck,
aj
