I know this isn't something I'm throwing a guess out there for, but has anyone heard of the hybrid RB30-DETT? Someone took an aussie Nissan car of some kind with a RB30-DE I believe.. then re-inforced the bottom end and threw either a RB-25 or RB-26 head on it! I heard a guy at the local import shop talking about this. Apparently you have to also drill part of the head or block for a "guide pin" of some sort to fit and align properly. It was interesting to hear about, to say the least. Finally, the last thing that the Skyline needs to compete with the Supra - more displacement.