Maybe you should've said "favorite individual car." If you're actually asking which of those is the best (i.e. fastest), there is absolutely no question that it's the GT-One Road Car. This is a pretty odd and extremely unbalanced poll.
The only road cars that can get more than 900 HP and weigh less than 1200kg are the Speed 12, the Nissan R390 and the GT-One, and the GT-One is by far the best. Completely stock it's 900kg with 600 HP. Not even any race cars can beat that except the F1's, the Escudo, the R390 and the 787B.