Your favorite mufflers for your Magnum?

Dynomax Ultra Flows, Borla, Jones Maxflow, or Magnaflows are going to flow well. I've used Magnaflows, Maxflows and Ultra flows and the Ultra and Max were on the quieter end. They all get loud when you get on it but cruise pretty quietly.

Its going to come down to your taste and what you can put up with, what is loud to some folks is too quiet to others. Listening to videos typically doesn't capture the true sound very well let alone the rpm range and inside the cabin. Tube size and routing layout can alter sound as well. Best bet is hit some car shows and listen or get with a local shop who will work with you on swapping out the mufflers until you get what you want.