Originally Posted by AutoSlash

You need to rent a minimum of an ICAR, or to put it another way, you can choose from the UC section if you reserve anything other an an ECAR, CCAR, or EXAR (Manager's Special).

A a UC location you can choose from whatever is in the UC section. Typically you'd find FCARs and above here with an ICAR/SCAR sprinked in occasionally.

At a non-UC location it's a one-class upgrade up to an FCAR, although you might do better if you ask and/or the staff is feeling generous, or they've run out of everything else.