1. No...The tank doesn't need to be empty. But my personal preference is to remove the tank all together. It doesn't take much more, and it give you a lot more room to work with.
2&3. If you don't have access to a laptop, then the only way to get the map on the bike is to put it on the PCIII before putting it on the bike.
4. Powercommander should have a map on their website. If not, try the maps posted by members here.
5. Just follow instructions... It's not too bad of an install.
What can I say...I like the factory bikes!