You have to remember the three levels of parts.
Mercedes Parts = having the Star.
OEM = made by the same as above but wont (or may not) have the Star (OEM usually means Original Equipment Manufacturer).
Aftermarket = something different, but not necessarily bad.
I have bought a lot of parts here. Some have been in the blue box with the Star, most have been OEM and don't come in the blue box (but many still have the MB part number and Star on the part). I have been satisfied with every part I've purchased, perfect fit and perfect performance.
Remember, on many parts just having the blue box and Star will raise the price somewhat. If you can get the same part for a few dollars less by forgoing the blue box, what's the problem?
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.