The rear camber is not adjustable as it comes from the factory. You can purchase aftermarket solutions. There are Kmac adjustable bushings that go in the lower control arms. Alternatively there are adjustable camber strut arms. I went with the Kmac bushings. They work very well, however, getting the old bushings out can be extremely difficult. Both solutions are listed on ebay, but you may have search for them under SLK320.

Here is a link to the upper camber arms:http://cgi.ebay.com/ebaymotors/REAR-...Q5fCarQ5fParts

Here is a link to the Kmac bushings: http://cgi.ebay.com/ebaymotors/KMAC-...item3a4cee05e5