To be clear, window motors changed in early 73 when the circuit breakers were added under the dash. They have a black plastic cover and look almost like the e28 rear door motors with identical mounting points and two wires. They bolt right in, you don’t swap regulators, wires are plug and play, the e28 motors for all four locations in a coupe. I think torque is a bit better with e28 but the best return for your effort is cleaning the steel wheels and ball bearings, if you don’t you will have the same issues.