Your passing stats for Culpepper, Manning, Hasselbeck, Bulger, Favre and Brooks are overly generous.
Your rushing stats for Alexander, Williams, James, Faulk, T.Jones and probably Westbrook are a bit generous. I don't think Ahman is going to get 3350 receiving yards either.
I also try not to overproject on rushing TDs since they vary a lot from season to season. I seem to have magically lost my spreadsheets for rushing stats the last three seasons, but I usually set my upper limit for rushing TDs in the 16-17 range since anything higher is very rare.
You're being pretty optimistic for Kellen Winslow.
Everything else looks fine with the exception of Randy Moss's TDs.
In general you seem to be a bit optimistic about your stats compared to me.