I located the bulletin. It was issued to dealer Parts Managers from the Department Manager, Service & Parts Sales on June 5, 2006. The following are the highlights:

"Mobil 1 ESP Formula M 5W-40 is formulated to meet the latest Mercedes-Benz engine oil specification MB 229.51. This new formulation is designed to offer high levels of performance for Mercedes-Benz diesel and gasoline engines as detailed in the Dealer Technical Bulletin P-B-18.00/17d dated April 13, 2006."

"Mobil 1 ESP Formula M 5W-40 replaces Mobil 1 OW-40, and will be provided to dealers based on deployment through ExxonMobil distributor network."

"To prepare for the transition you must draw down Mobil 1 0W-40 bulk tanks to a minimum 20% level in preparation for the new product."

The 190E can use any oil, synthetic and conventional, based on the old approved products chart. I think most folks use a high quality 10W-40 in those cars.