I think it'd be a nice little addition to have an extra column on the cartel page, where you see how much rep every player has gained for their specific cartel.
Right now you have Level, Role, Days, Last Active. So basically to add a column 'Rep' and there it adds automatically the rep that is gained per player for the cartel.

Perhaps have it only visible for cartel members/leaders even, or however the capo sets it.

Would be another good way for tracking cartel member activity.