Yep it's got it. I picked up my express a few weeks ago, noticed the MDS drone on the way home but it wasn't that bad with the stock exhaust. Switched to a Mufflex exhaust using the 14" magnaflow muffler last week and the MDS drone is very noticeable now. Using tow/haul mode switches it off and also manually shifting. Here is a quote lifted from another thread:
This is direct from the chat with the Ram Hemi Engineers.
To disable the MDS, put your shifter from D to 5 (as displayed on the EVIC or cluster). With the console shifter, this is just one hit to the left. With the column shifter you need to push the +- button - one time.
Your trans will still shift up and down automatically through all the gears.
Tow/haul button is not the correct method.
It doesn't sound that great when MDS is active but it didn't stop me from getting an exhaust. I wouldn't say it sounds horrible. MDS is usually only active while cruising so you're not on the throttle enough to really notice and after a week it didn't bug me that much.
What exhaust systems are you looking at? I'm very happy with my Mufflex system.