Perhaps you mean E320 V6? Might look like a V8 with so many plugs (2 per cylinder).

There is a 'special' wrench. It is a 17mm open end wrench with a 'dog leg'. Back in the day, wrenches with this shape were fairly common but now not so much.

You can get the wrench the big boys use from the dealer. Part No. 110 589 01 01 00. It is made by Hazet and called a valve adjust tool. Price is about $33. It has exactly the right offset to catch the front of the boot and press it off. After looking at the SnapOn I decided to get the MB one.

You can also contact Ohlord a frequent contributor on these sites who has a similar tool for a few dollars less. I think he has some package 'deals' including radio keys and cluster removal tools as well.