Man, that seems to me like it would be a PITA.
The One thing that May be an issue, is the temp control on the passenger side.? I'm not sure how (by installing a Dual system), the driver and passenger can Adjust their Temperatures seperately, without other adjustments to the system, other than just the head unit.
I would assume there'd be Seperate switches or relays running to each side of the Unit, in order for this to be accomplished.
Unless they're built into the unit itself?
But even then, wouldn't the duct work have to have "gates in them with switches to allow let's say the driver Temp.to be at 65 and the passenger's to be at 85?
It's too EARLY!
~Ray