hi chris,
i've got a passage gt with a rb25 and 25 box... goes in relatively easy.
brake - 33 gts-t rotors/calipers fit all round on import struts (so coupe is fine) mine has 33 gts-t calipers, and rotors re-drilled to 4 stud.
the front hubs can be drilled to 5 stud, but the rears use a 'square' plate so it cant be drilled to suit, you can use Z31 rear hubs i believe, or possibly even get billet ones, depending on how much power you plan on throwing at it.
rear swaps - i assume you just mean tail lights? 99% sure they are a straight swap.
lsd - my factory lsd seems pretty decent, doesnt single peg. i do have a tomei 2 way sitting in the shed for it as well though.
my 31 has quite a few mods done, so if you have any questions can shoot me a pm.