I had to re-read your post before commenting, and when I got to "any cons?", decided it is worth it.
My thoughts? Don't do it. External speakers are just plain tasteless
Think of the volumes you have to keep it pumped to so that you can hear the music over the road/wind noise, through the helmet and, (hopefully), your earplugs. Even if you reduce the volume when puttering around in town, you will still be annoying anyone nearby.
Is your bike nothing but a mobile "Boombox" that you can inflict your " excellent
" taste in music on the rest of the world?
Okay, okay, maybe I'm feeling a bit crabby this morning. But 30 years ago, (feels like 10....really!:rolleyes
, I did blast the neighbourhood with an overstressed Blaupunkt in a Datsun 510. Today I remember it with some embarrassment, even though I
had excellent taste too.
Stick with earbuds or helmet speakers and enjoy the tunes for yourself.
(And keep Vancouver Island the idyllic place I like to remember it as)