"1) Why did they kill the real brother of Dasha (Offcource to let Kot go n kill him outside the prison so no suspicion... but wouldn't it just be easier to "just" kill Kot like they killed Dashas brother and let the brother live (offcource than the movie would be 20 min long, but still its pretty stupid decision by the prison authority)" They killed her brother so they could give Kot his documents and get him out of the prison (Dasha's brother's sentence was about to end). They wanted to free Kot because they were paid to by Kot's friend on the outside...eh...Dimon.
"2) Who the hell would want to kill Kot? It obviously was some fat "businessman", but what was the motives? He was involved in killing of FSB agent but it seemed like no1 knew about it... or maybe its cos of that situation on a petrol station? I thought it was Dimon, but than he died protecting him so that was really great start of the movie. Buslov was thinking a lot on that i guess. As far as i can see no1 had serious reason to kill Kot." The cops wanted to kill Kot because he was too much of a liability, if he was caught by police again the whole thing about his release from prison would come back to haunt the cops who freed him. Aka if he is caught his fake passport (the one with Dasha's brother's name) isn't going to fly and that would start an investigation that eventually would lead to the prison cops who were paid to free him and who killed Dasha's brother.
"3) Kot wanted to start over but wouldn't it be easier to sell his half of car show room than let the girl rob tourist agency? He knew she was desperate at that stage of her life... he could predict she would do smthn stupid..." That question doesn't really make much sense.
"4) When he met her, why didn't he just tell her the truth straight away? Or he could just give her a letter n say that her bro is dead n then leave..." He felt responsible for her brother's death, because her brother was killed because of him.
Now my own opinion, honestly I liked the first one better, the second one was kind of kind of riding on the tittle a little bit even though it is still a worthy movie to watch.