I was wondering if a Turbo assembly fro a 88 GL-10 turbo wagon would fit on a 84 GL wagon? what modifications would I have to do if any?

I think you need the up pipe, down pipe and the 02 sensor moves a little otherwise its been done. Search the 80's forum a little more if you haven't had luck finding exact info.

If the 84 wasnt set up from the factory as a turbo, then no...not really.

It needs to have MPFI, a bigger fuel pump and lines, ECU and harness.

Also will need a turbo cross-member, so the up pipe will clear.