I agree with the recommendations of The Mafia Runner and Juicy Fruit. Both of those are really good stoires. I haven't read the other recommended story, therefore I have no opinion on that one. I would also recommend:
Love Ain't Blind by sauropod
and the in-progress sequel You Ain't Seen Nothing Yet.
The sequel hasn't been updated in a few months, but it is really good so far and I have hope it will be continued as the author is still actively updating another, non-mafia, story on AFF.