I love my Uly, it’s my 9to5 ride. I purposely keep the stock exhaust because I’m old and an aftermarket exhaust droning away at 80mph for hours at a time isn’t appealing to me. My more playful bikes have aftermarket exhaust.
The factory exhaust with the exhaust servo does a fine job. Also makes a great crash plate. :-) With the exception of looking like a 5 year old welded it and it weighing about 247lbs I’m happy enough.
A friend has a dual exhaust D&D on his X12S - sounds amazing, but ear plugs are a must.