IMHO... set a maximum speed instead of constant speed... like restricting speed on school buses

 

It will limit the speed by limiting the max RPM of the motor.
It cannot be adjusted while driving.

 

the only thing i can think of is like an aftermarket ignition system with a rev limiter . dunno about the one your referring too . the late model gmc i had was how shall we say tweaked and would run high 12's and if i would let any of the kids or the wife borrow it i plugged it in with the power programmer and put a restriction on the speed and the revs as they , and i know from catching them in the act , drove it HARD !!!!!!. so maybe some sort of engine control system if ya lean towards the dark side ??????

 

I have decieded that this part is not for me. If anyone else is interested look up eBay Item number: 200196471809. If you collect NOS parts, this one comes with the box.