as an engineering student, ANSI standards are extremely reliable; since a single jack is designed to a safety factor of 1.5, those things could probably support 8000 pounds (safety factor 2) without even getting close to the young's modulus.

in other words, you could probably sit the entire Z on a single stand and that stand won't budge, much less using two or four stands and splitting the Z's 3300 pound weight across those stands. the fact there's an opening doesn't affect the strength of the design much. would probably be able to safely support 6000 pounds if it were completely enclosed. "regular" jackstands are full of holes too! do you not trust those?

I would consider shelling out a good amount of money for the hub-stands; I see them at race garages. to be clearer, it would be those jackstands that mount on the hub, sort of like the dynapack hub dynos:
http://www2.ecutek.com.au/images/Dyn...b-dyno-600.jpg

Inventor said in actual testing a single stand was loaded to 10,100 lbs. and was still linear (showing no sign of yielding) at that load. the hub stands would be great, but what if you want to work on brakes, replace rotors, wheel bearings, etc. Isn't the stand going to be in the way?

Then, I guess having hub stands would be kind of bad... although other than that, they'd be cool. Would be nice for pulling an engine. Don't have to worry about it rolling away or any other kind of problem with it being jacked up.

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