Got mine installed today, quite pleased. Shout out to
@Rockcrawlindude for the ratchet strap idea, that worked great to keep the mufflers in place during fitting, etc.
I also fired it up briefly without any muffler - that'll wake up the neighbors! Sounded awesome.
With windows down it sounds great; rumbly, throaty, and when you goose it, it gets a little raspy/metallic, sort of like the exhaust note on some Mustang V8's. With windows up the exhaust note is muted, but definitely more present than it was with the stock system at anything but zero throttle. When coasting/zero throttle, it's basically silent as the old system was.
Similarly, on the highway it's noticeable in the cab (windows up). I am very aware of vehicle sounds (and in the house, as well), constantly listening for any sound that's out of place - sorta sucks to be honest, haha.. So I was listening acutely.. But it's not loud in the cab nor is it unpleasant, there's just a low rumble now when before it was very quiet (well, it was quiet after I ditched the Duratracs). I didn't spend much time on the highway, but varied the speed (mid-60's up to 80 or so) and the rumble didn't vary much. Truth be told, I've never experienced a true 'drone' with an exhaust that is known to cause them, but I did not notice any annoying frequencies or pitch shifting (apart from throttle related) or anything at all when MDS started. My MDS seems to rarely kick on on the highway, but in the few times it did around town, nothing really changed audibly from the exhaust, just the engine noise changes a bit.
If i had my druthers, I would have probably bought the Borla 'Touring' model, if they made one.... but they don't! So here I am. For now, I'm happy with it. Going to sleep on it for a few weeks (keeping my stock exhaust in the basement) but am 98% sure it's a keeper.