I looked into this when I bought my '95 E220 last year. There are a number of firms offering to retro fit, if they're doing it properly with original MB parts, the cost will be about £1500 and they will need the car for 2-3 days.
'08 Chrysler 300CRD (MB OM 642 engine)
'95 E220 estate
'89 230TE (R.I.P.)