One of my friends in the tire world put me in touch with a technical expert at Bridgestone - as he put it, he's
"the second best person (the best one only speaks Japanese) to be able to really get into it with you about really detailed info on the RE040's". I just got off the phone with this contact, and this is what he said about them. This summary is virtually a verbatim transcript of his words and our conversation.
First, he said that
all of the Bridgestone Potenza RE040 models (and also the RE050) are designed for specific cars. If you look at the
spec sheet for the RE040, you will see that
every tire size is designed for a specific vehicle. They work with the auto manufacturer to match the design criteria of the car manufacturer for the tires (precise handling, dry traction, wet traction, etc) along with the characteristics of the car, including its weight, its handling (propensity towards oversteer/understeer, etc). Thus the 215/45ZR17 size is optimized for the Lexus IS300, etc. And tires which come in different sizes front vs rear for a given car are indeed optimized for that particular end of that particular car.
Second, he said that the NSX sizes are indeed corner-specific. A left front 215/40-17 tire is different from a right front 215/40-17 tire. He wasn't sure exactly how, or whether the tires shared exactly the same design features as the RE010 tires for the '91-01 sizes, but he said that the tires are not symmetric and are not interchangeable from one side to the other. He was surprised to hear that there is no sidewall marking to indicate which side the tire should be mounted on, but assured me that the left tire was still different from the right tire.
Finally, I expressed to him the concerns that some have raised about how a "twelve year old tire", such as the RE010 tire which was designed specifically for the NSX, might compare with a newer-generation general-purpose tire such as the Bridgestone S-03 which is designed to be used on many vehicles. He said that it depends on the car in question. For example, with a family car like a Ford Taurus or Honda Accord, the design objectives of an OEM tire are geared towards that particular vehicle, and might seek to maximize ride comfort and minimize noise, while providing decent but not superb dry cornering traction. In that case, the driver who is concerned about performance characteristics such as dry traction and precise handling might indeed find that the S-03 performs better for his preferences than the OEM tire. However, he said that with a high-performance sports car like the NSX or S2000, the design objectives of the OEM tire are to maximize those same performance characteristics. As a result, the older OEM tire that is designed specifically for that vehicle can easily provide better performance than a newer tire which is designed to be used on many different vehicles.