The 94 factory turbo pump will work just fine on an 89, but you should match it with the G code injectors. The other codes are different, there is some info here on different flow rates, but I don't know where it is or who posted it much less what it means. I like the Delphi injectors better than the Stanadynes. If you can get the Delphi equivalent of Gs that would be better. Others will say you should either keep a stock pump and injectors or just spring for a Moose Pump from Mel or a DPS turbo cal pump from Ken. I would actually suggest either of those actions over the factory turbo fuel system. Good luck,
JD