Thanks for the responses,
The Maxx Fan Deluxe is nice, but I am going with the Turbo Maxx in the bedroom also, leaving the existing vent in place. If was scott is saying is the same on my new unit, the wiring "should" be there for 12 volts. We bought a 300BH with the second AC capable 50 amp upgrade, so I know there should be a 120 line there also. We'll see.
I was questioning whether to remove the existing fan in the bathroom, but BDLuke convinced me to leave and just splice into the linek.