Check out ScottB's post, a few items down.
He has an entire 87-88 setup for sale, including the controleer, harness, and motors.
It'll make a nice plug 'n' play upgrade.
You can fix most anything that's wrong with the motors in about a half hour. Much less complicated than the array of relays and switches. The motor control works on current draw, so there are no fussy limit switches.