[elhigh]

Doesn't compute as far as I'm concerned. Don't tire manufacturers recommend we replace tires if they get cuts in them?

More edges to cog into the driving surface and help clear water from under the tire probably help with inclement weather traction, but the fact is most of the time the roadways aren't wet or snowy. I can see siping having an effect on snow traction, but really don't we expect the manufacturer to have done a decent job in the first place? If I'm running on snows, I'll trust the original engineers to have known what they were about and put in the right number of sipes to give good traction, but not enough to reduce the tire to a big black KOOSH tire.

Tire shops aren't engineers. I'll pass on this added-cost point-of-sale "service."