According to the excellent web site
www.mulsannecorner.comthe Carrera GT produces 343 pounds (156kg) at 150 mph (240k)
Aerodynamic pressure increases as the square of the speed increase so you can extrapolate the other figures from this.
The factory claims 640 lbs at 205 mph. F 192, R 448.
These are very low figures compared to racing cars but they don't have the ride height compression problems to deal with. The Le Mans Bentleys produce 3000 lbs at 150 mph