I did the work myself, so that´s $0 for labor.
APR does not charge anything for the file update, that´s another $0.
15whp is almost 20hp maybe more if the temperature conditions had been the same.
The flapper thing is a permanent 15whp increase. at least in the R platform for around $200 dollars.
The head porting is $2,000 plus a very heavy and expensive shipping, not counting another 4 to $6,000 for a bt kit, or adding the ferrea valves kit and rods+pistons while you are at it that might well be another 2k or more.
That is over 10k not including labor or other expenses.
I´m still investigating the rear pcv catch can solution to see if that could be something that could work.