There are people out there BESIDES the dealer that are capable of balancing these wheels. The challenge is finding one of them. The two piece clip weights as used by MB are available through tire supply companies such as Myers and All Tire Supply. There is a special tool that is also available on the aftermarket. Failing the correct weights it can be done well with tape weights in the hands of someone who knows how to do it.
There is NOTHING magic about balancing these wheels if you have a halfway decent computer balancer and the proper attitude. In 20 minutes I could teach a high school kid how to do it properly. The challenge is finding someone who cares about doing it right.