That's interesting. But if there have been failures of the metal ones, that would be known, I think. Also I do not use any thich oils (synthetic only). So would it be possible to fit the metal ones on so I don't have to ever do this again... To me, b/c I am way too cynical, it just seems like a cost saving measure. But I should probably be kinder

__________________
2008 S550
2010 GLK350
1997 E420 (retired)
2005 CLK500 (retired)