We will book Luxury now, its ~85$ more than full (can't book premium for that period). And if we should get a Town Car we will definitely talk to them nicely, and rather take a Altima. Actually we were really tempted with the Altima/Camry category. I think those are nice cars with a good fuel economy (LV-Grand Canyon trip etc.). But considering 4 people* in the car a little more luxury wouldn't hurt and the additional cost for upgrade and fuel is reasonable too.

Having never driven any of the LCARs I would favor the Hunday Genesis. A 3series would certainly be a nice drive, but maybe a little cramped in the back. The other LCARs should be fine too, though I also assume the STS/DTS will be out of the fleet by then.

(* Actually 6 people in an ICAR+LCAR so the luggage wont be a big issue )

Anyways - I also noticed that the price is fluctuating, even 4 months in advance . So we will definitely keep checking if the price goes down.

I also think $327 for 2 weeks premium is a really nice price, but I accept we can't have that around New Year . Have fun in MIA.