A special tool is required if you are only replacing the seal and not resealing the cam cover itself. If you take the cam cover off you can tap the cam seal into the cover with just a hammer. Most of the time it is the 'U' seal at the bottom of the cam cover that is doing most of the leaking. In that case you should get a tube of the MB Black sealer for the edge of the 'U' seal that butts up against the head. The tricky part is installing the cam cover over the top of the 'U' seal and without disturbing the cam seal. You may be better off leaving this for your MB mechanic.... But if you do tackle the job yourself, then be patient, and if it leaks the first time, then learn from your mistake and try again.
Now you mentioned oil consumption. That is most likely NOT from the oil leak at the cam cover, but rather from the valve seals. Is there a deposit of carbon from the spark plugs?? I saw a bad case of carbon on the plugs just yesterday at work, and the customer declined the repairs.
Eithe rway, Good luck!