do some autox's, hehe, that'll take some tire off the the outside edge :D With my setup, I can't get enough negative camber up front, the outside corners wear extremely fast. Of course, my car sees only highway duty on the way to autox or the track.
If you're having issues in the rear, the camber arms that are available should get you where you need to be very easily.
Parking Lot Hero
2008 WRX daily driver
2003 ZX3 23D Autox Car 42 FSP
"Hella Functional - Raced, Not Hard Parked"