I remember we discussed this a while back and there was a little bit of confusion on what the actual force numbers of the spoiler were. I ran across this in a DC press release about the Crossfire:
Powered by an electric motor, the rear spoiler deploys automatically when car speed rises above 90 km/h. Deployment takes less than five seconds and the spoiler generates 356 Newtons of downforce to the rear of Crossfire at 129 km/h. The spoiler can be deployed manually at lower speeds using a switch on the centre console. Raised edges to the sides and trailing edge of the spoiler enhance its performance and it works in conjunction with the lower venturi created by the diffusers around the dual exhausts.
I ran those numbers through a conversion calculator for those of us who don't speak metric 
and that works out to 80 lbs of downforce at 80.1 mph.