Fantasy: Should i keep all my WR's or try to make a trade for QB or RB?

Your team is pretty solid, but to get the QB that'll put you over the top I would go with trading Desean Jackson and Manningham combined or even Sims Walker and Manningham and go try and get a Philip Rivers, Kurt Warner, Brett Favre, Carson Palmer, or Roethlisberger. You have the backup WR's to be fine in that position. And if you can find a team with one of those QB's see if they will throw in a more consistent DEF and you add Helbeck or Sanchez. Good luck with the rest of your season. I see nothing wrong with your RB's. Jackson will finish off strong and Thomas should be solid the rest of the year as well as Mendenhall.