Head pipes are the same. The tuned pipes are the same. The waterbox's are different, where the hose from the tuned pipe to the waterbox connects is offset on some models and in the middle on others. One from a gsx cannot go on a xp or spx, it may work on a gtx though. I had sandblasted and painted a waterbox and went to install it on a spx and realized it would not fit, it was from a gsx and it was very clear when comparing the 2 that the inlet was in different spots.