I just purchased an 08 MB with a 3.0 liter cdi in it and in the manual it states that the recommended 229.51 oils are:
Mobil 1 ESP Formula M 5W-40
Valvoline SynPower MST 5W-30
ELF Solaris LSX 5W-30
However I was at the local Napa auto parts store today and saw a bottle of Valvoline SynPower 5-40...