Do any members have experience using Pirelli Carving Edge Run Flat tires on a 2011 or newer XJL Supercharged Jag? We have 245/40Z/R20s on the front and 275/35Z/R20s on the rear. We have been told by our Jag dealership that the only tire they recommend is the Pirelli SottoZero II for my vehicle--which would cost over $2000. They say that the Run Flats provide a much less desirable ride on a car like mine. Discount Tires, where I've always purchased my tires in the past, has recommended that I use the Pirelli Carving Edge, which is a Run Flat, in the same size. They say I won't notice much difference and the cost is about 1/2 of the cost of the SottoZeros. I have never used a Run Flat tire and have been told by my son, who drives a BMW, that came with Run Flat tires, that they are quite a bit stiffer. Any critiques or comments would be greatly appreciated as the snow is about ready to fly in Colorado.