I just figured out why the hell I get green marks on the left side of my pants!!
 

Apearently the plastic is extreamly crappy on the housing of the seat belt on the S4. If you have like a cell phone in your left pocket and the pants rub against the side getting of the car, it smears on your pants/shorts (Ok you gotto be tall like 6'4 or something) . I have like 3-4 brand new pants and shorts completely wasted because of that. Not like the car does not cost an arm and a leg...

Wonder if I can get audi to pay for it :)

What are you talking about? What is green that is leaving the marks?
 

The seat belt mechanism is black. What does "like" a cell phone have to do with it?

Apearently the plastic housing smears dark green, allthough the
 

Housing is black. Cellphone etc provides a harder surface helping the smearing. U can test it or I can upload pictures if u like.

How in the world would black plastic smear dark green?

Well, the guy who checks to make sure that the seatbelt..
 

housing doesn't rub against the pants of people 6'4" or taller,who carry phones in their left pocket, may have been off the day your car was built.