So I put a Solo exhaust on my 2014 RT AWD a couple months ago. Solo uses a "J" pipe to replace the resonator, i want back twice for J pipe adjustment. The first adjustment helped the MDS drone but it was still pretty loud. The second adjustment dropped the tone of the entire exhaust from idle all the way through to WOT but did not help the drone. Solo has now produced a spring loaded exhaust throttling device (not sure what the real term is for them) but they create a variable exhaust pipe dimension depending on exhaust gas flow. When on 8 cyl and with foot on the gas the valve is full open and when the MDS kicks in and exhaust flow drops the spring closes down the exhaust pipe dimension to tune it to the 4 cylinder operation. Apparently this is a copy of what Dodge has on the new V8's with MDS. The drone is effectively gone and the car is SO MUCH better on the highway under lite to mid throttle. It works well, haven't seen any performance differences. I recorded my 3 month fuel use average and now I will do the same to see if there is any fuel consumption difference. All in all i am impressed with how the Solo guys have been on this and have helped out without question and without additional costs.