I tried to look up m104 spark plug removal,and got bits of info.I thought I would write this for thoose wanting to service their vehicles.
The following plugs are safe to use.All copper core plugs,platinum,and iridium with fine wire in tip do not produce enough spark for our ignition.
There is one brand of Autolites Platinums I may try one day,with large tip.
Ok,to change plugs,Unplug Maf sensor first.Lossen clamps on crossover tube and remove 3 bolts.Pull crossover up and away.Next the black cover on engine with allen bolts remove,and remove cover.Next you see your 3 plug wires,the other 3 are under the coils.Remove wire and blow down in plug hole with air.Then remove plug(you might have to use long neddle nose pliers to remove lose plug.Do all 3.Next unplug Coil power supply wire,and remove wire from other plug.Now grasp coil with both hands and use brut strenght to pull coil up and out of the way.Change plug,and repeat other 2 .
Install everything in reverse.
NOTE*If you can afford it change your wires and coil boots.If you see your rpms wiggle at idle its the old plug wires.
I hope this helped someone.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran