I’ve only heard the dyna in person. Not the Delkevic. So I can only go by video sound.
Modifying the stock muffler has proven fairly successful the way DBM did it. And I’ve heard other people like the mods they did to it.
I don’t mind the quietness of the stock muffler, but the high pitched whistle is pretty annoying (mostly at idle speed).
I think just about any muffler is going to drone at highway speed on a thumper. Turning 4000rpm at 60mph is going to drone…. And it’ll drone even more as you climb the rpm ladder
Give it a shot when you get to that stage. It’s personally more than I would want to spend when a dyna sounds pretty darn good in person and can be had for like $40 plus some extra hardware, etc. The dyna sounds pretty good at highway speed (and you won’t hear that in many videos).