255/45/17 is a good choice and fills out the wheel opening nicely. A friend of mine has these on his 95GT and no clearance issues. Its just a little wider and taller, but not enough to throw your speedo off more than 1 mph at 65mph. 275/40/17 are a bit much on 17x8s, a lot of sidewall flex, will take some getting used to, but I it looks cool. This would be my 1st choice if you were going with 17x9 rims.