I don't know if you would really want to do that. Unibodys don't have the structural support for making a convertible. It would collapse like a house of cards unless you reinforce the structure. It would be very expensive and your car would be conciderably heavier, but different from anything else. If your up for the challange, then kudos to you.
Here's another one I did of my car
-tinted windows
-recessed grills
-ram air hood
-chrome rims
-wraparound spoiler
-gto headlights
