Changing transmissions will likely result in the loss of your column shifter and in turn convert your truck from a 3 passenger vehicle to only 2.
I have a 4 speed (floor shift) in my 52 and have no problems with two passengers. Not that any of the AD trucks are really 3 passenger trucks, at least not 3 full size people. The shifter does not make much difference either way.
Another way of putting it, I have never had to say "you can't ride with me because my truck has a floor shifter", never...
Grigg