I had the 555's on my 2000 GT and will be putting the 555's on the front of my cobra eventually. They are a great tire, and the mileage isn't too bad, but not near as long as a standard radial will get you. I had them on my GT for about 25k miles when I sold it. Having rotated the tires once...they had about 60-70% tread left. Obviously, with my lead foot, the original rear tires were at the lower percentage rate...and the rotated rears were catching up. lol
None the less, great tire. Worked very well in wet and dry conditions. For $5 more, definitely get them.
"When I know more, I'll be forthcoming. Or I won't be forthcoming, and I'll be honestly deceptive." - Les Miles