The corbin solo seats for the R100GS are hard as a rock and weigh about as much as one too. Seriously, you'll be amazed by how heavy it is. A friend of mine lent me one to try and I rode with it for an afternoon. That's all my ass could handle. SERIOUSLY uncomfortable. I ended up going with NOS BMW seat, but after a lot of miles in that thing I don't much like the shape of it. It really locks you into one position and doesn't allow for much scooting around. I've never tried one of the touratech saddles, but I like the shape of them.