Adambomb,
The MB is far different then the PSD. IDI versus DI for one, lower injection pressure, on and on. Further check some of the other site like Infopop about Lovercraft.
I would say that a MB in a So CA climate is a perfect engine for one tank WVO use. As long as you add injection line heaters I think you really can't go wrong. Plus the cost of these cars is what $10K or less. So for most that is a throw away car so if you get 50-70K miles out of it.
The 7.3 and 6.0 PSD is a great motor also for WVO but it needs the oil hot to inject properly. Since you can't add injection line heaters there is no way to get hot oil to the injectors not on a cold engine.
Erick