I had all 4 replaced, Silverstar's by the dealer, BIG MISTAKE! Back twice still bad, one was pointing to the ground and one up in the trees, the other 2 who knows? I ended up doing it myself. The passenger side outer was a pain, but can be done! Note: small hands and long fingers are a plus, also if you are a contortionist with a rubber neck it is a definite plus!
Good Luck!