I am not sure about the low chance of happening. There have been members on here who said they babied their cars and still dropped the valve seat. plus, you never know how it was handled by the previous owner(s).
People have said they have found remanufactured heads for around $500, then installed themselves. you should be able to do the full swap for $2000 or so, if you do the labor.
Hope all goes well for you.
I made the decision not to replace my head. I don't want to drop 25% of the value of a car that I don't know how much longer I will keep anyway. of course, I have been saying for the last 6 years I was going to replace the old turd, and never have....
Defending the reputation of the red-headed step-child of the focus world for far too long.