You also have Tornado (U.K.), GTD (U.K.), and DRB (Aust.) for choices too.
Come on over to
www.gt40s.com and do some surfin/research over there.
I too am looking for a kit in the future but my personal timing isn't going to be until a couple years down the road most likely.
You could also buy a "used" GT-40 that has been on the road a while and mod/restore it to your liking too.