Port & Polish would show upper RPM gains. Mainly HP due to better breathing. TQ may drop a little, but negligable.
Expect to pick up noticeable power above 4000-4500RPM.
The SVT of course would benefit much better then a Std Duratec because of it's better breathing components and CR.
This is an good option when getting your heads done. (Like during a 3L swap or engine rebuild) I personally wouldn't pull my heads just to port & polish them. That's fairly expensive Bang for your buck.
