They all seem to differ, that would seem very excessive boost to me. I ran 18psi on a standard bottom end and made 199bhp at the flywheel at a rolling road day at SCA in Norwich.

In saying the boost sounds excessive we did get my brothers 100k mile bottom end running 21psi peak and holding 19psi but it was my good mate Rob that set it all up for us and it was only done as we didin't care how long it lasted as we had a big build planned. Incidentally the engine never did fail and we got bored of waiting so just pulled it out for the rebuild after 18 months of abuse