Hi Crankin, I'm not sure which trunk closing device you're talking about. All 220's are equipped with pneumatic "closing assist" for the doors and trunk lid. This feature is previously known from the W140. If you're talking about the feature that allows you to touch the big red switch to automatically close and lock the trunk from the open position, I think you're out of luck. It's a hydraulic system that uses it's own dedicated pump, as well as several other parts. I haven't seen any retro-fit info, so I doubt it's available as an add-on. Sorry