They removed the information so the consumers were not confused about any old information still listed on the site. The new information will be up there when they start to ship the vehicles along with the correct options/features and any other information that has changed between the first annoucement and production.
Well the convertible seems to be back on the website, and it looks like the GTP model lost some hp, how I don't know. If you look in the performance section of the hardtop, it says "GTP powered by an all new 227hp HO V6". Could that be a loss due to the extra weight?
The convertible definitely looks nice with the top down; I think GM does a real nice job of that (read: 9-3, XLR, Corvette, now G6), although I'm still not entirely sold on the looks with the top up. Maybe it's just because I'm used to my coupe, but with the convertiable, the lines to the rear just aren't near as smooth as the coupes. Granted, it would be near impossible to be as smooth.