AMM will be about $450 from the dealer or about $250 from this site. I bought mine from here, to support the site. Don't bother with the cheap ($100 or less) ones on eBay, they are new and good quality, but are typically the wrong Bosch part number and will make your car behave weirdly (trust me, I tried it). You can get the correct one from eBay for $250, but why not support this site?

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280