Fuel pump relay would be the most convenient point to immobilise it from. All done now though . You can never be too secure, I guess a tracker is best though. I've seen a shocking number of neighbours cars 'dissappear', returning only as they were tracked. Thieving scum .

autozen, it's a Brabus 3.6 but I posted under '300E' as the fuel pump arrangement is the same. Interestingly (and very unfortunately) though in and around the London lots of W124 and W123 Mercs were stolen by a gang(s?) who broke them and sent them off to Africa so I feel doubly threatened.