My sales guy said the big boy AC had also rear controls. I'm thinking it's a bigger condenser, fan, maybe rear evaporator. I don't have my can yet, so this post is speculation.
My cargo van's AC (without the rear unit) puts out very cold air. Unfortunately, in humid areas, the system ices up, and airflow drops to near nothing even at full fan speed. I have to turn off the A/C, and wait until the airflow increases and eventually warms up. Recirc sort of helps, but recirc automatically turns off after a while.I'd have to believe the Vclass, being more of a standard Benz, will come standard with the cold a.c. Can't have Gramma sweating in the rear!