Trade Addai or R. Grant for Miles Austin?

[roundBallJef]

I'm in a dynasty league, and am deep at RB (MJD, Steven Jackson, Addai, Grant, Jamaal Charles, Shonn Geene, James Davis IR), but need help at WR.

Thinking of going after Miles Austin, would Addai or Grant be a good trade straight up, which would be better? Other suggestions?

Thanks, WHIR