dont know exact differences but 84 and 85 fall in one catagory and years 86 and 87 fall into another there are minor differences like i have an 85 and pulled a headlight cover from a 87 and i had to really massage it to fit in front of the hood it was more angular than my 85. also when buying from ebay they like to use words like zenki or kouki trueno or levin. trueno=popupheadlights, levin=set in headlights, i believe zenki=84-85 and kouki=86-87. i know within the years gts and sr5 body parts are interchangeable. hope it helps