Milling the heads, cheap insurance.

 

Another thing nobody mentioned yet, if you do mill the heads, you'll get better compression. Not much change in performance, but you might see a few horses. Check your block for warpage too, although it ISN'T likely, I have seen a deck warped and in need of millilng due to extensive overheating. Better safe than sorry, right?

 

if your gonna start milling your heads your gonna have to be ready for leaky intake gasket and flow issues because they are sure to follow. Sick