hardtop and Rollbar installs

I am looking at purchasing a Miata, but the ones local that I have found don't have a rollbar or hardtop. does anyone know about the install of these? I am really leaning toward the hardtop, but need someone to help with understanding. I don't want to buy something that will be very difficult to install. would rather go hardtop, but how much cheaper will the install of a rollbar be?

Please Help thanks

question reguarding the Hardtop, how well does it do with rollover, does it add extra protection? does it work as well as a rollbar, or atleast as well as a hardtop FC?