What kind of engine do you have? I did mine on my W124 (M104 engine), and for a dim-wrench like me who has never done a radiator before, it took all of an hour and a half for the removal and subsequent install of the new one. Did the p's and q's for another 1/2 hour on the following day before starting up the car and testing...
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