I think that's the point with these stands. Check out this page on their website. It shows a pinch weld chassis on the stand. The pinch weld actually sits inside the pad and the pad kinda locks on to the base. The base is 12"x16". The car's not going anywhere when its on these things.
http://jackpointjackstands.com/Optio...lications.html
There's a real long thread on Rennlist about these things, if you're interested in what other owners think about them. (sorry its Porsche guys)
Jackpoint Jackstands ??? - Rennlist Discussion Forums