I own an 09'Challenger R/T w/ Zoomers since September 10th. I already ran 1350-miles with a road-trip to Nevada last Saturday.

Not sure if those who bought the, "Electronics Convenience Group package" with the Vehicle Information Center (VIC) display anything either; also there is no mention of the MDS function being displayed on the VIC in the car manual either. From my experience and road trip the MDS comes on if you are cruising at a constant speed, no matter if its 10,20,35, 55, 65, 75, and or +100 MPH. If you are at a constant speed for awhile the MDS will engage automaticly. You can actually hear the displacement take place from 8-to-4 cylinders and then back to 4-to-8 cylinders when you demand more ponies. The displacement is noticed more from the tone of the engine at higher (+55 MPH) cruising speeds. On my road trip to Nevada I was traveling at 70-85 MPH when I remained constant at 70 MPH the MDS engaged and stood "on" until I demanded lots more ponies to pass slow vehicles. I also noticed that my 5.7L Hemi loves 70-75 MPH, you remain constant and in cruise mode. Also Zoomers exhaust notes do not change with MDS engaged; unless you demand alot more ponies the MDS disengages and the hot rod loud rumble arrive as seen on the video below. True with any exhaust. When at constant cruising speeds of 70-75 MPH you just hear the rumble of the twin exhaust.

Metal's 09' Challenger R/T - with Zoomers exhaust