I changed the plugs on my 98 e-320 at 100K. I'm pretty sure it's the same engine and plug configuration. They were really tight and I must admit it was scary trying to break them loose, but I was able to do it. You need to take your time. A plug socket fits nicely into the spark plug well. First, you need to remove the engine shroud and it also helps to remove the coil packs (one per cylinder) that are attached to the valve covers. Mark them for location and note which wire on the coil pack (there are two) go to which plug. I also removed the air cleaner and air cleaner housing (all of it) to help get to the plugs on that side of the motor. Carefully remove the plug wires from the plugs. Obviously you don't want to be pulling on the plug wires, just the boots. A boot puller is handy to do this. Twist boots to help break them loose from the plug, then pull, gently with even pressure. Apply anti-sieze to plug threads, and di-electric grease to boots and neosporin to any skinned knuckles. For the correct plugs, call Phil at Fastlane. He'll make sure you get the correct ones. I think I paid between $125 and $150 for the 12 plugs required. I don't think I'd be buying Benz parts from Autozone. Don't forget to take your time. Good luck.