Ok. You need an ECU that has the features to run that engine, which in your case (if it's a stock GSR) would be a P72. This is the 92-95 GSR ECU, so it can properly control the IAB (secondary intake butterflies on the GSR manifold) and has a knock sensor. You already have a OBD2-ODB1 adapter harness, so that part is done.

You will need to have the ECU chipped. This is usually around $50, and can be done by a local shop or someone like me (if I was still local) or sometimes by whoever sells you the Hondata system. Chipping allows the ECU to operate from non-stock programs, which is what tuning software generates. There are also some other minor things which may need to be done to the ECU depending on which Hondata product you use.

The Hondata system is a little box/board/etc that plugs into/onto the ECU and allows the (chipped) ECU to use the Hondata software. Some of the systems add more features, like datalogging, user-settable launch control, etc., so check out Hondata's site for more info on the specifics of each system.

I'm some salesman for Hondata or anything, and there are other options out there also which all have their pros and cons. I'm just answering your Hondata related question.