You'd first have to determine whether your insurer charges UM as a single coverage applicable to all of your vehicles (that's what mine does), or if they charge you UM per vehicle. If it's a single coverage, you can't drop it unless you drop it completely. UM/UIM relates to injuries only, has nothing to do with the car you're driving, or any damages, etc.

My $.02, I would not drop it in FL, for the reasons already noted. Too many uninsured drivers, and also a low minimum limit required by law ($10k per person/$20k per accident). And a LOT of drivers in FL who have insurance carry those minimum limits...remember UM is also UIM, as in Underinsured Motorist. If you get hurt by an uninsured/underinsured motorist, you're going to be screwed. Also, how much UM/UIM coverage are you carrying?