I think most people don't understand the REAL reason for the different deck styles. Subaru started closing the deck on all engines with the EA71 I believe. This was to combat headgasket issues. Up until the EJ series all engines were closed deck. But with the newer style of engine it wasn't needed on NA engines. They stuck with it on the turbo engines for a while though. Why they stopped doing it is up for grabs. Could be that even the EJ20G/EJ22T didn't need to be closed deck to begin with, and some EJ20G's weren't, but who knows what changed between the open and closed deck versions. Or it could be that with the EJ20H and EJ20K they could manufacture engines that wouldn't blow the HG's. As I said, I don't know for certain.