Solved

Reputation

So as far as I understand it reputation points are gained when racing (and winning) against people stronger than you in terms of their level and reputation (not sure about this one). But imagine a situation when every player within a league has the same level and reputation. So is it going to slowly go up, if everyone is getting equal amount of wins, or is it going to stay the same? And if some lower level players will come in, will it cause everyone else to lose reputation? And is it possible to reach 10k reputation in this case? 

So noone knows the answer? :(

That's right reputation goes up very slowly if everyone in league has a similar reputation points or even in some cases down if others have less reputation than you. Therefore you need to be in a stronger league if you want to gain more reputation. Think of it as a see-saw it balances itself with teams in league weaker gets stronger and stronger gets weaker to reach equilibrium!