Originally Posted by nsxtasy

As I mentioned earlier, Kumho makes a lot of tires with the Ecsta name, everything from Ecsta V710 track tires to Ecsta STX truck tires. One of their best-selling Ecsta tires was the Kumho Ecsta Supra 712, and I suspect this is the one you're referring to. It was an okay "budget performance tire" in the late 1990s and earlier part of this decade, but suffered by comparison when the Yokohama ES100 was introduced in 2001-2002. (The Tire Rack did a comparison of the two, and the ES100 beat the 712 in all 23 of the 23 characteristics tested.) Its lack of performance against the competition is the reason Kumho then set to work developing its successor, which is the SPT and is much better than the 712 in every possible way.

The basic objective in choosing a size for street tires is to select a size that has the same outer diameter as the stock tires. This maintains the accuracy of the speedometer and odometer and the general appearance of the stock tires, and avoids downsides such as rubbing on the wheel wells or fenders. 215/40-16 is too small for a GS-R (2.9 percent smaller outer diameter than stock) and 225/45-16 is too big (2.3 percent larger than stock, which will rub). On 16" wheels on a GS-R, you need either 205/45-16 (0.8 percent smaller than stock) or 215/45-16 (0.7 percent larger, which will not rub). Most tires come in one size or the other, not both; the SPT comes in 205/45-16. If you're looking for what the SPT has to offer - very good performance with very good treadlife at a very good price - then get the SPT in 205/45-16.