Search the forums a bit more and I think you will find the differences in the spring/shock assemblies. Everything is identical except for the lower wishbone stud on the shock. One is completely threaded the other is not. The one that is not will require a slight enlargement of the mounting hole in the wishbone, using a dremel tool or similar...not a big deal.

The spring/shock assembly designed for the full size spare tire bracket commonly seen in Europe is probably valved differently for the additional weight. I would think it would be fine to use..maybe just a little stiffer than the one designed with the underbody spare.......