I had the local dealer fit the Boom stage 1 upgrade to my bike, it's louder but the sound quality isn't much better.
try this lot out.
quizguy, here is a link that is very good. I have a Rockford Fosgate system in my 2016 Streetglide and love it.
Hi Qg. Why don’t you use the supplied Harley helmet headset or get some. You may be using earplugs at speed on the big rides when listening to music is good. Headsets sound good even at low volume levels. Plus you get the phone / gps / intercom compatibility. You don’t sound like a knucklehead when riding in built up areas with too loud music. It’s what I do.