Mag's last point about his choice selection is what made it for me as well: cost. M104s are god awfully cheap compared to any other I6 option that I know of short of an L series. Displacement helps the choice, but in the end, the cost is what makes it *my* personal choice. Obviously, places where RB engines are more available, That's going to skew things in their favor, to the point that if I was on the other side of the world, I'd probably go RB, simply because people know it far better.
That being said, M104s might be even cheaper for you guys than they are for us. There's some Korean company that's still building them under license that sells a bunch of models (and has for around a decade) in australia.
But enough derailing the thread. b/w the 2JZ and the RB26,I would go with the 2JZ, for the reasons I posted on the first page.