Here's a picture of the new tires that I'll be getting. They're actually slightly different to the ones that I have on the car at the moment, since they appear have additional bands towards the edges of the contact area. These are Proxes T1R tires, which probably weren't yet out when I purchased my T1S tires.
Looking at the specifications for the two tires, I'm not actually sure which one is supposed to the better and how they actually differ? The T1S tire has a higher speed rating? Otherwise, they seem to offer the same amount of traction and wear?