Yeah, we aren't talking about the same thing here. I have always seen the Y-Pipe refered to as teh pipe coming out of the intercooler that feeds the intake manifolds. The metal one in teh picture with the sensor sticking out of it is the one I am talking about and the one that want to use with the NeedsWings Intake.

The one you are talking about IS #12 in the diagram. It is made of plastic. Should be easy to get from a Benz dealer.