Check out DD VO-M 6.5. These are a mid range driver and have some pretty good mid bass. They are a tight squeeze in the RG Fairing (13 and below). If you have a 15 or newer, you'll have to cut the speaker pods.
As another option, I just helped a buddy install the DD CXS 6.5s in his Street Glide. These are a coax speaker, but I was impressed with the lower end response. They are capable of handling 150-200w, so with the right tuning, you could get a lot from these speakers and they fit with zero issue on any any model, to include going in the tour pack.
As another option, I just helped a buddy install the DD CXS 6.5s in his Street Glide. These are a coax speaker, but I was impressed with the lower end response. They are capable of handling 150-200w, so with the right tuning, you could get a lot from these speakers and they fit with zero issue on any any model, to include going in the tour pack.