The Mustang is only reservable if you book that class but as a practical matter - no one would want to have their fleet so heavy on Chrysler 200s, VW Beetles and the like... if you're renting a convertible, there's a good chance of getting a Mustang or Camaro - just no right to complain if you don't.

If it matters what you get and renting a car is a big occasion, you might do well to consider National/Alamo through one of the UK-based brokers where you can pick your own car (from the correct class) and wait for a better one to come along if there's nothing there when you arrive.

I do think you'd like the Genesis V6 though - it has a great noise at full chat, comfortable seats, soft handling and can break traction at the back if you try (it has 90 hp more than the CV). LAX (or anyone else) won't be keeping Crown Vics back; if they have a surplus they'll be given out to renters who've reserved classes A through F when they're low and will be defleeted when they get old (which has probably happened by now).