[American Dave]

Problem: Tight clearances with the S65 Engine combined thick oil can lead to bearing shell wear thru to the copper inside the shells. Once you get metal in your oil going thru your engine, well its not going to end well. Engine oil analysis is a good idea but wont necessarily save you your engine from failure. Replacing old bearings with VAC coated bearings is good preventative maintenance. There are new bearings coming "Clevite" which are tiny bit smaller and thus give you more clearance in theory. Those bearings have not been released to the public for sale as yet but should be soon I believe. The old bearings in 2007-2009 M3 S65 engine were made of lead / copper while in 2010 onwards model the new bearings are made of tin / aluminium.