When I ordered a new set of ignition wires from Caliber Motors, they sent me Bosch which I assumed to be OEM replacements. The wires are not as heavy as the ones that came in my 300E but I can't speak to whether the quality is better or worse.

The removable ends appear to be the same as the original ones.

I think that most of the time the problems people have with these plug wires it that they damage them trying to take them off the plug w/o the proper tool. I've learned to spray the inside of the boots with H/D silicon spray and that makes it a snap to pull the boots off w/o damaging them.