Ken: (this is for USDM Cars)
98, No AC except as a dealer option. 01 AC standard.
98, faux CF gauge cluster trim, 01 same trim but with other faux CF pieces in the center console, door trim pieces, etc
98 CW wheels, 01 gunmetal wheels
98 no immobilizer, 01 immobilizer
98 supposedly slower ECU, 01 supposedly faster (never saw proof)
98 97-98 intake cam, 01 practically a CTR intake cam.
98 type-r key, 01 normal new style acura key
98 leather covered shift knob, 01 "ti coated" shift knob
different floormats IIRC, or maybe 00 was the unique one and 01 went back to the older style.. I forget..

uhmm.. that's all I can think of off the top of my head.