I agree I think Cody is the better player, not just because he has great speed, but I think he is a playmaker also who will fight for the QB. Spears is a great player, but I think Cody has the more playmaking ability than Spears does and one big play can change the ball game.
I like the idea of "tweeners", I mean thats what Robiarre Smith was. He was a "twenner" and look how he did with us playing the DE. He played DT in Tennesse. Cody is the same way. He played some DE in college, I think if I remember right what USC did was let him play DT but on 3rd downs put him on the outside and let him rush the QB with his great speed.
One thing is, I don't like the trading down theory. We are at #13, and we don't know when we will get this high of a pick again. (Hopefully not next season) There is still great talent at #13 and you never know somebody could fall though the cracks like Derrick Johnson. Highly unlikely, but you never know. Keep the pick, take BPA.