Okay ive been through this exacly wen i had my 2000 gt and put a 97 engine gtp in it. Let just say its gonna bee oneeeee big head ache . First off ur better off to swap the whole indash harnesses and engine bay harneses and that includes the abs modual that goes with the proper harness. And as for the cab/rear harness you will have to reground your fuel pump gauge a different way because 97 harnesses are compatible wats so ever with the 98-03. It took me a week roughly to do all this and u also would have to swap the air bags to keep them with the proper harneses.. Let me know how u do if anyquestions just pm me
