My dealer quoted me a price of $1600 to do my 3.2L M104 on my W124.
The current head gasket is on borrowed time (no overheating and no oil in the coolant tank yet), but I am certain that I will be posting a thread about how to go about doing this by next year...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car