well not sure, dont quote me on this, i heard it kills boost BUT you make the same power because less boost is required to make the same power........im probably going to eventually mate the M62 to a FR head, if thats the way i go, only time and mony will tell
i think if you get a good three angle job and such, i think the cheapest iv heard of is 600, and then if you want to throw in larger valve train well there you go your already better off w/ the FR head
the three angle valve job is really kind of a funny story as i learned from kickn. call ford and ask them about it and you will be suprised it really isnt much to advertise about apparently. its always good tho, like mofo says, to have a second head to do the work on and just swap.