I'm also interested in upgraded speakers for my 18 CVO RG that has factory Boom II speakers and amps. The speakers are less than stellar by far and I'm sure one day they will need replacing but I'd like to keep all 3 of the amps. Yes I added speakers to the lowers I installed as well and upgraded to the GTS head unit last year so I now have a similar set up to the 2019 CVO SG. Best factory system Harley has ever come up with IMO.
So Scott7d, you have the 2 Boom II amps and 4 Boom II speakers on your 20 CVO RG and you replaced just the fairing speakers and you are happy with the upgrade to the sinister speakers correct? I couldn't find the RG setup on their website.
newseultra07 I believe you have an Ultra which does not come with Boom II but Boom I? So a totally different system other than the head unit I think? While not apples and apples I still understand where you're coming from.
So maybe some of the better informed folks out there could explain why we couldn't take both sets of speaker leads per speaker with the Boom II setup and splice together the pos. to pos. and the neg. to the neg. that go the bi-amped? factory system to get ALL the power from the Boom II amps into a really good quality replacement speaker?? Someone has to be able to figure out a way to build a better mouse trap.

And thanks Scott for getting the ball rolling on this and the thorough description of what you have accomplished.
Please don't laugh to hard at my ignorance on this subject but hopefully someone in the know can take a minute and shed some light for the rest of us.
TIA