MB price is rather low on the 300D water pump IF the core is a genuine MB water pump. Look for a little MB star on the old pump casting. Exchange price should be about $ 60 to $ 75 or so.
2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg
And remember folks, Only You Can Prevent Hilliary.