Wires

Yup, They were always inflated to spec, treadwear was uniform until the suffered accelerated wear. I'm going to go for Audi asked for a lower cost tire option, Pirelli changed compounds on the inner surfaces (because, heh, you wouldn't hit those until the warranty is done, right?) that didn't have the same longitivty properties.

I was in a tire shop once talking to the guy and complaining about the Michelin MXM4's that came on our Acura about what a piece of garbage they were (didn't handle well dry, wet or snow). He said even though the name is the same, doesn't mean that the OEM tire = tire shop tire. I know on BMW, their desired spec tire gets a star stamped on the sidewall. Same model name, but will be listed as BMW star with the model. Those have compound changes to meet the performance and lifetime for a particular car model.