I see some folks are puting these on their x's and I was wondering how these differ from some of the others I've seen and priced out. The others seem to be about $40 and these seem to be about $80 in price. Is there something makes them them soo much better? I went to a VIP and an Advanced Auto Parts store and they all had the $40 price, none in stock, but they where the cheaper ones. I figured they all where the same. Maybe I'm just getting hosed on the price for these ones?