Question one: If you mean the ADB and Fastboot drivers, I have some old ones stored in a thread here
http://xdaforums.com/showthread.php?t=2087337 The Fastboot zip will serve you well in that case, if on Windows.
Question two: The "unofficial" versions are all based on the official one (they all work by the same principle, just masked so you don't see it).
Which one to use? Swift tutorial:
1.The official one. If that doesn't work, you move to
2.The one that looks best to you. And if that doesn't work onto
3.Any other one. If you have enough un-luck for this one to not work
4. Go back to the official one and retrace all your steps! Get the code again, reinstall the drivers, try another PC.