A Mini that came to me as an old convertible project.
Not done very well, the roll bar was only made 1mm thick metal.
Well, the next thing to do was to cut off the rest of the roof and just have the screen, well this means the sills need strengthening. I designed and made 3mm thick inner sills, with extra plates to stop the car folding in the middle.
And also modify the fuel tank so the filler is inside the boot. Quite an easy mod. as long as you properly empty the tank.