I think the RC-3 has some updated features like an extra button or two, but is otherwise just a new version of the RC-2. I'd assume the same about the RC-30.
You mean original drum tracks? There are drum machines, drum plugins for DAWs (I think -- probably VST plugins) and drum freeware you can download. On the loopers, many of them have several built-in drum tracks, like on the RC-2 it has a bunch...like 50 or something that you can cycle through.