What is this thing, why do I need it, and why is there a Mercedes part number on it?
 

I bought a sway bar drop link online and there’s a little rubber piece on the top that’s cracked with the part number 020 060 013 012. Upon googling it, it appears to be a Mercedes part number

http://forums.pelicanparts.com/uploa...1600973817.jpg
http://forums.pelicanparts.com/uploa...1600973817.jpg
http://forums.pelicanparts.com/uploa...1600973908.jpg

That looks like it was the rubber boot for the ball joint.

Lots of Porsche parts have MB part numbers on them. Same suppliers...

Anyone know where I can find a replacement?

This. You can find parts from Audis, VW, Mercedes and other German brands that are the same parts bin. Early 928s used a Mercedes automatic transmission.

As I remember the cruise control computer CPU on my 85 Carrera is identical to the Mercedes unit from the same year.

more curious as to what car this droplink belongs to.
sure not an aircooled 911

Maybe it's a '99 Boxster? :)

its a 964 c4 front sway bar drop link,, you totally need it