Referring to backmarkers as "monkeys at the back" and hinting that his employer does not give equal chance to their drivers, when they claim they do count towards that, for staters I suppose.
in my book "cocky little shit" is a less severe insult than "monkey". i'm saying that yes, he is good, but not very humble, while he is saying that the other drivers are completely useless and shouldn't even be there.
in english "piece of shit" is a very strong insult, but "little shit" isn't as strong. it means someone who is flippant or who acts without regard for the feelings of others.