In japan early model gen 1's came with the 4g63 turbo stock, and no the 4g63 head will not bolt to the g54G engine 2.6 is chain drive and 2.0 and 2.4 are belt for one.
If your looking to swap a turbo 2.0 check out http://www.projectzerog.com has ever thing you should need to know about a rwd swap for the 2.0 and even the 2.4


89 2 dr turbo diesel
89/88 "Backwoods sas"