Can someone gimme a small list of ways to raise rep with ncr?
Wiki is your friend here. Sell items to traders.
I am asking about that is it possible to get Bozar from NCR Guard. Is it?
As RavenousRat said, it is impossible.
Karma implemented??

It has no impact in the game yet, afaik.
Who is in control of "The Den" ? I wanna pay the gang for buffing up the local militia so damn much, Oorah!
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Log in, press P twice, click "Statistics" and go at the bottom to see the current factions that control towns.