Hankook has them listed but I don't think they're availiable right now. I'll check my distributor.
All rally tires are heavy, I wouldn't be suprised if my wheel/tire combo approaches 40-50# easily.
I think most think the Michelin/Pirellis are better from what I've heard. In my direct experience I wouldn't spend the money on silverstones when I can get the other for only a bit more.