BuddyPress.org

I try to customize the User Name in the activity feed (add a Group Name),
so I thought to to use add_filter on the bp_get_activity_action

1. Question
Is there a better way to do this?
2. Question
How can I do the same to the comments?

add_filter( 'bp_get_activity_action', array( $this, 'filter_header_content' ) );
public function filter_header_content($args){     
    global $activities_template;
    $displayName = $activities_template->activity->display_name;
    $action = $activities_template->activity->action;
    $newName = 'New Name';
    return str_replace($displayName, $newName, $action);
}