add'l info re: the GTX1
In response to your concerns... I spoke with Mark (contact info below) & had a short discussion with him. I also let him know there have been several GT owners with questions & he said he'd be happy to answer any, so feel free to give him a call if you're interested in this new car. He was to be sending me some additional info via e-mail, but this hasn't arrived yet.
1) there is a window in the back so that when the top is on, it's 100% sealed.
2) they only tested it w/the top on up to 120 mph & had no problem at all. the reason they stopped at 120 (according to Mark) was not because they were afraid of problems w/the top breaking off, but because that's apparently all the space they had for testing. (this to me is an unacceptable answer as it would need to be tested at high speeds to know if you're going to have a problem with it, at least for those of us that would want to go much faster than 120).
3) according to them, because it has a good seal all the way around it won't leak - not sure how thoroughly this has been tested though
The gentleman I spoke with, Mark Garrish, is selling the GTX1 (920-242-9156). I believe he also owns one. He did mention about 20 other options that anyone calling him might want to inquire about (ie, different types of doors including the "Enzo Ferrari" doors, seat upgrade, cup holders, nab system, etc...)
MJ