well its simple you complete the game and then you might unlock cool fast cars but only some have convertibale roof so be carefull what car you buy...when you have a car press start and then go to options then game then convertibale if its there select yes or no if convertibale isent there you cant do it.
you get convertible cars in group 3 and group 4
No
a convertible
no
Nope, sorry
Midnight club
no
well you can if you crash with a bike
Mods
Saleen s281
Yes
South Central Premium Expansion and the Two car packs
you can't