Quickest/fastest quarter mile on 15 inch "cosmetic" all season tires like BFG T/As (etc)?

How can this be? I know the rules about the tires but something doesn't add up.
Firestone Wide Oval (the tires that came from the factory on the fastest cars in F.A.S.T. racing) are "S" rated which means that they're only approved for 112 mph. Many cars are running well past this. The fastest cars in this class are evidentially running ~140mph! No way in hell would I go 140mph on a tire that isn't made to go faster than 112.

Are these people absolutely insane or is the rating known to be falsely low? It's one or the other...
That speed rating is for continuous use, like for an hour or two across Montana. They are perfectly safe for 130 or 140 mph for three or four seconds. (Unless, of course, the have been softened to silly putty).
T/A radials turned my low 11 second car into a mid 13s car. (Had to make a points race, and one slick was flat.)
I would not even bother taking a car to the track on any of the above mentioned cosmetic tires.