Yeah I would not have sunk my time into that personally but these guys are going for a number not working to a budget, if they find 5 things which gain them 2hp then they're up 10hp. It would be a very expensive/time consuming 10hp but still helps them towards that number. If anything this whole thing might raise some interest in the hobby and those interested enough will learn that there are easier ways to wake a 318 up instead of trying to copy what they're doing.
Aftermarket heads offer so much power potential that these little gains have become mostly unnecessary unless racing in a highly competitive class or like ya said for something like this build.