I had the same rear camber problem on the right side. I certainly can understand why you would not want to go with the pressed in adjustable bushing. I did do it that way. Luckily I had the spring compression tool and a press to get the bushing out.


Here is a set of adjustable camber arms on ebay that you could use.


http://www.ebay.com/itm/Mercedes-Benz-Rear-Camber-Kit-Adjustable-97-12-SLK-R170-R171-R172-Made-In-USA-/301453835690?hash=item46300c7daa&vxp=mtr