I have to agree with everyone else, I've done the swap myself on an '07 with the intention of running boost and nitrous. I did do the Eagle head swap so there were no port mismatches, but I still had to do the timing cover and bracket, but I got a great deal from a semi-local guy so it was worth it for me.
I did get gains in the top end on the nitrous compared to the stock manifold, but it was definitely more of a dog in the bottom end.
Now, I've got it on my '09 which is a forged 349, running 15psi, and has the nitrous installed but isn't tuned for it yet. The stock manifold won't handle that kind of abuse for long, and it looks damned sexy doing it since mine's powdercoated metallic black.