You took out your power steering pump, and left the fluid that was in the rack in there? Keep an eye on it- without pressurized fluid lubricating an internal needle bearing in the servo valve, the needles tend to start falling out & can seize your steering. You can ask me how I know if you want, but I have a feeling you've got an idea, lol...

 

**** sorry I ment cruise control, lol how did I get that messed up???

 

Back to the origonal thread topic:

I can't see for sure, but The wires were extended from the area of the stock boost control.

You mistery part could be a substitute boost control solenoid.
It would have had hoses from the manifold & to the waste gate.

The stock B/C vents off some of the pressure to the waste gate.
This one would hold back pressure from the waste gate (if that's what it is/was)

 

I've got an s4 would I have a boost control silenoid??? Also the wire looks pretty freakin shot so I just rewired it just incase it was doing something major.