I have been reading, learning, and taking notes about MB diesels for over a year now. I just cant seem to get one question answered though, do I want a 300SD/L or a 350SD/L? Whats the difference? There seems to be sooo much info on both- some of which I think is just the authors point of view- that I feel awesomely overwhelmed by it all ! Just to elaborate further- one person says that the I5(300SD) needs much more attention/ maintenance than the I6(350SD). Others have said that the 350's have serious motor failures. As you well know I could go on about the "mines better because..." antic. So far I know that a cast iron head sounds like a better motor, but I really like the looks of the 350's with the aluminum. Mabe someone can clue me in. I am sure all that reads this will have something to say and I cant wait to read it!