The OEM tires on this car (my wife's) is Goodyear F1-GS-D2 (Z rated). I never liked them from the beginning - they tend to move too much laterally. However, my threadmarks are arriving at just over 31K,...not that bad for an ultra HP tire (if I was the one driving all the time, it wouldn't have been that good!!!). At 30K, these tires howl like a fox -man are they noisy!!!! Anyway, it's time for all four to go and after checking out The Rack, I noticed that the GS-D2-Z has been replaced with the GS-D3-Y (or W, I don't recall, but not Z). What is the difference? I love to see that Z on the side wall!!! I have narrowed my choices to the GS-D3, the RE730 and the ContiSportContact. The B'Stone S03 was eliminated for poor wear, don't know exactly why I took out the B'Stone RE750 and I didn't even consider the Dunlops due to poor cornering performance (I have them on my Turbo-Z now and they are not that great). I absolutely love the RE-71, but that's history!!! Like I said earlier, my Darling Half drives the car most of the time. When I do drive it (usually for service or some long trip) the needle usually stays over 85. So what replacement do I get now. After some research, it's lookin more and more like the GS-D3 will be the choice. But that lateral instability thing can sometimes get quite scary, when one has 3 kids and a wife riding along!!! Advice please. Thanks.