ProchargerCobra, you are right... Your tires are Z rated and the Supercar tires are YR rated. Take a look at the speed ratings and you will notice Z = 149+ and YR = 186+.

Before you try to make the tires he chose look inferior to yours you might want to do your own research before you look like a dumbass.

And furthermore, I was interested in these tires as well, but if you didn't tell me about a gash in them prior to me driving 80 miles to come get them I'd be pretty pissed as well.