Rear Camber

This is interesting. You wouldn't need very much at all to make a big difference. Last time I got an alignment I had them set the front front the specified 0,6 camber to 0,4 and it almost completely eliminated understeer. I'm sure the amount that you would need to do it to make a substantial difference in handling would be so minor that you wouldn't have to worry about the increased wear on components. That is if you're actually trying to improve handling and not just get the stanced look. The optimum change for handling probably wouldn't even be visible. This being said, my real concern would be going to far, since it's not really adjustable, and then not having enough negative camber left in the front to prevent it from plowing throw corners.