I'm confused! I want to get a new Festool drill motor with the various interchangeable chucks. 14.4 volts is fine for me. Can anyone explain how each of these tools differ from one another: 564374 - 564520 - 564522 - ? Two of them look the same, and two of them have similar batteries. What would be the advantage of one design over the other, and what battery is more preferential. They all carry the same price tag, BTW. Thanks much for any information.