I believe that early Legacy/Imprezzas had 4.11 trans, at least in Australia. But if I go the 3.9 how much difference will it make to climbing ability? I'm going to do the CIG Locker (you call it Lincoln Locker) thing, but I thought I might as well do the transmission changeover as well while I'm at it.
You're right about the regulations for mods here. I'm in South Australia which is a bit more rural than the eastern states, so we can get away with a bit more than them, but a 2" lift is about all that is street legal here. Even some fairly tame engine transplants are illegal here. I was going to fit a blower to my EA82 n/a motor, but it is illegal, so I will probably just go twin carby with dual port heads, but that's after I have the trans sorted out.