I suspect that is aimed at the naturally aspirated builds.

Having seen some of the stuff that has gone in to your engine I think you have a very top end build and you don't need to add to that spec. BUT if you do then Mark would spec the engine in terms of bore etc. I think Mark liked the 14mm extra height for the Rod angles (excuse the Rod pun) but he said to me that unless I was 100% convinced on saving 25kg then do not bother with the Alloy block as my 2.2 is fine.