Slightly OT: I don't get the haters. If someone wants to spray their car, good for them. It is the better method. Not everyone has the money, tools or equipment to do that. These 3 threads have proven that rolling is a viable alternative, and convinced me to give it a whirl, and I've sprayed cars in the past. I like rolling.

Back OT: the paint needs time to cure, which pretty much means the solvents have to evaporate and allow the finish to harden. The bulk of this will take place over 24 hrs, but complete hardening will take weeks to accomplish. More heat means faster drying time. Remember, body shops use heat lamps and ovens to 'bake' the finish. So your Florida M-B should be ready to drive within 24-48 hrs. However, you won't want to wax or polish the finish for probably 2-3 months. Waxing it will seal the paint, and you don't want that right away as it's still going to be evaporating solvents for awhile.

As for way up north, I'd keep the thing in a heated environment for the 24 hr period (or a little longer and keep it as warm as possible to speed the initial curing.