The muffler design can in itself reduce drone. The hard part is finding the balance between drone canceling and exhaust note. The MBRP mufflers are great at canceling drone, I ran their street series for about a year. The problem for me was I went from a Pypes MMS to the MBRP Street series in the factory location. It was a huge step down in exhaust note, but also carried virtually no drone. I ended up going with the Magnaflow standard mufflers with custom 4" tips. It gave me back some exhaust note with no noticeable drone. I admit though, with the red race BOV it was hard to tell if the exhaust had a drone over the BOV.
As far as superior exhaust note, nothing sounds better than a mid mounted muffler, in my opinion. The only way I can see to have a desired exhaust note without the drone, is to have an electronic bypass valve system in the exhaust, much like the GT350R uses. It could be set up to open/close at specific TPS voltage. Not sure how far someone really wants to go to engineer the perfect exhaust. What is acceptable drone to one may differ to another. The same goes for exhaust note. A lot of people can't stand the Pypes M80's. I loved them, just not on a stock cam. The car had a terrible drone at specific rpm's, I simply didn't cruise at those rpm's lol. Electronic cutouts and more exhaust piping will add weight to a car, so I can't say it's the best in performance options.
Beyond that, the only other known way to control drone is via resonators. Resonators are typically placed after the midpipe but before the mufflers. The Challenger's use resonators after the muffler, but I'm not sure how well they perform that far rear of the cabin. We are, after all, talking about drone the driver will hear, not necessarily what someone outside the vehicle hears. It's all theory here, as not many people go that route in an effort to reduce drone, it's usually done to enhance the exhaust note. I think if you want to reduce drone, mid-mounting the mufflers is the worst thing you could do. The best thing would be to stick with the factory muffler location and add resonators after the midpipe. Beyond that, it's choosing the least drone prone muffler type/style.