Don't have an R-Series But
I ended up having a Carven TR installed myself. Putting around the drone is minimal, when lugging up a hill at 55-65 (~1550-1600 RPM) you get some drone. When MDS is on, the drone gets a bit more noticeable at those RPM ranges. When I'm cruising at 70+ I barely notice the exhaust. My wife complained about it once or twice, I usually kill MDS if she complains and it's better for her. For me it isn't a huge deal though, I don't mind the slight drone. The TR of course is the quieter of the two, but still sounds great to me, I'd say it's a tad louder than my 18" Magnaflow but no where near as loud as I would've thought for a 14.5" straight through muffler!