if you just mean that you want to fit a different - non-standard - body onto your buggy then simply measure the distancefrom the centre of the front wheel to the centre of the back wheel and the width between the 2 fronts and the 2 backs and then go to your LHS and start measuring shells till you find one that fits and you like the look of.
then it is just a case of fitting aftermarket body posts somewhere on your Buggy to mount the shell onto