I bought the Hogtunes for my 03 RG, and while they sounded a bit better, they certainly didn't live up to my expectations. I don't know if the problem is with the speakers per se, but rather the general noise level of the bike at highway speeds. My friends with batwings love their speakers, but remember, they're almost a foot closer to their speakers than we are. All told, I was underwhelmed.
I've pretty much given up on the radio at highway speeds. It is a bit better with CDs or MP3s, but not much. Just my opinion, though.
If you do go with the Hogtunes, be sure to let them know you have an 03; they have a plastic gasket they send you to install with the speakers to keep the cones from pressing into the edge of the fairing's speaker cutout.
As to antennas, I have a short stubby (about a foot long) that seems to work about as well as the stock. But here in the LA basin, you could probably get good reception with a bent coathanger.