pkramer,

Unfortunately, your brake pad wear is probably due to the ESP system. If you have tires that do not match well at all four corners, it fools the ESP system and it starts applying brakes at different corners under different conditions.

With the ESP system, you can't replace one bad tire, or even one axle, they must be exactly the same at all four corners. This means you must replace tires in sets of four. Have you replaced tires in anything less than sets of four along the way? If so, I expect that is your problem. I know its a bad deal, but there it is.

Good luck,