Had semi performance mufflers on my 2014 Charger SRT and no resonators. Recently I had Powersticks installed and these are very close to straight through pipes. I'm now noticing that the MDS (switching to 4 cylinders) almost never comes on. The only time I'm noticing it turning on is when I'm decelerating. It used to come on all of the time when I was maintaining my speed (above something like 30mph). That does not happen any longer. Does anyone know if something like back pressure might trigger the MDS to kick on? It is certainly related to the change in the exhaust as it was working fine the day before and the day after it changed.