Jim Horst, dieselengineer here on the site, has the Max in his Doge and swears by it.Still need good wiring back to the brakes though, which in your case is already done. Only other thing to do is disc brakes. That is a pricey upgrade.
After having the Ford version of the hydraulic integration in my truck, I think that is the only way I will go in the future for towing heavy trailers.
The Ford controller being integrated to all the truck's systems, steps it up a bit. At speeds lower then 20 mph the system voltage is reduced about 20% to reduce the tugging that is common in high gain settings and stop and go traffic.
Another super feature is the hill hold. When going up hill and stopped, the brakes will hold for approximately 2 seconds while you transition from brake to throttle.