This is from a completely stock S5 vert. I've searched the forum and found other guys posting 9 pin connectors, but not anything like this. This car wasn't modded before I bought it, so what would this be for and did S5s come with this connector from the factory? I'm stumped

 

Looks more like random computer/electronics connector. I am pretty positive, it is not Mazda factory installed.

 

definitely nothing the car came with.

 

Definitely not factory. Looking at the connector (DB-15) and style/finish of the plastic part and cable, it might be from an early-model in-car cell phone system - usually the head unit got installed underneath one of the seats, with the handset portion installed to the right side of the center console.