There are currently only three hardtop for our car. The Porsche factory
top which is a 55lb. aluminum
top, Zientop which weights about the same (as the factory
top) once you remove the trunk and clamshell, and Stuggart
top, with I think is also aluminum.
The company you referred too, just sold the shells in Carbon Fiber for a very short while so finding one will be pretty hard. To be honest, the 55lb. factory hardtop is pretty light, and don't think the carbon fiber will make it to much lighter, or much of a difference. Also, since it will be painted you won't know it's carbon fiber so looks don't really have much to do with it.