I know it is ill advised but I ran some 15 year old Continentals when I swapped the original Fuchs back onto my car. They were obviously not very sticky but because of that it was a good way to learn how the 930 chassis reacts at the limit and the limits were fairly low because of the old, hard tires. As long as you aren't doing top speed runs the risks are pretty low.
I've always been the type to run tires until I can see the air in them but your mileage may vary.
930 Snow Launch by
willtel, on Flickr