hello, will buy me the w220 this summer and the closest choice is only about whether I should get the 320 or the 430. have the following questions: 1.are the consumption differences very low (0.5-1liter difference are very low) and most important: 2.are the engines having special problems that the other engine does not have?? (as for example the 6 cylinders of the e38 have much more probs than the 8 cylinders) it’s only about these questions everything else is with both gleic h. mfg