dont waste the money for the extra 20-30 hp.


Thats 4-5 grand for almost nothing.


To answer your question, it depends on what year GSR you have. If it's a 94-95, you're going to need an obd-2/obd-1 converter, because the ITR is an obd-2 setup. If you run 96 or newer, it should be a relatively straight swap.