the brake light switch provides power for the orange wire that is spliced into the orange/blue wire.

As the bottom diagram shows, the GPS portion is nothing more then a pass through. Meaning it doesn't map the 4/5/6 gear position into something other then what they are already mapped into, so the GPS restrictions are still in place.

Your better off doing the wire splices yourself instead of using the m-max.

Of course the M-Max gives you the nice coupler for the GPS, so you can pull that off the M-Max box, do your wire splice there, and use the couplers from the M-Max box so you don't need to mess up your stock wire harness.