well, there is no itr 'rear lip'. unless you are talking about the whole rear bumper.. but theres no difference between any 98-01 2dr rear bumpers.. RS, LS, GS, GSR or ITR. the only other thing i can think of is the OEM body kit, and the rear is two small pieces that go on the corners. they will not fit on a 94-97 rear bumper but they will fit on any 98-01. hih.