The only thing I've got to caution you is that it's not bug free, and is a bit larger than the original file.
The community builds have less bugs than the version still shipped by plimus or "other sources" (thanks to all the fixes of those involved). Imho you are really better off with the new builds

At least you have bought the game and can prove that if necessary for anything (who knows...)
Ah and a random note about boxed games, are you sure?
Imagine CDs that get lost, dusty, scratched, and tons of game boxes that fill rooms but have to be kept because they have the authentication codes...

Anyways, have fun now. Check the forum from time to time, there may be updates!