I came to find out yesterday that the two are not compatible. I bought a '99 GS-R PS Pump from B18curmama and slapped an AEM pulley on it. I did it b/c somewhere in the PS system, it was blowing a leak. Mine's is a '95 GS-R, and I ran into a totally frustrating problem with it.

The rack feeding hose (hose that routes next to the cam gears) has a different fitting into the power steering pump, as does the fitting on the pump. The fitting is larger on the 98+'s, and the bolt pattern is also different. I'm pretty sure the 10mm bolts are the same tho.

Even Duluth Acura Carland lists a (1) and (2) for different PS Pump parts.

< http://www.acuraautomotiveparts.net >

As of now, I'm running with no power steering and absolutely loving it. My only solution is to buy a need feed hose and replace. $102.99...yick.

 

After reading my own post, I realize that I must've traumatized my medulla oblongata b/c I sounded like a retard.

Anyways, the whole point of the post was that the older and newer pumps are different and require both the pump and a compatible hose for it to work.