Trans Modulator, '85 500SEL
 

I just noticed that the trans modulator on my car is red. I thought the white one was the right one for this model.

What would the difference be in performance?

By the way, I read here that you can adjust the modulator...is that the "t" handle under the rubber cap?

Yes, clockwise for harder shifts, counterclockwise for softer.

The red one fits a number of cars from 190E2.6 to 560SEL. It may have a different profile for movement versus vacuum but I doubt it would be so severe that a little adjustment couldn't make if work. You are right that your car should have the "Natural" one.