There are more aftermarket "lips" for the 89+ because, the aftermarket companies who made expensive lips for the certain bumper type said, our lip would look good on that front end. Lets spend some money to manufacture and mass produce this item then sell it to the general public so they can make their 89+ supra look even SEXIER....
Then someone said why didn't we do this for pre89.... crowd turns around and says are you serious look at that fugly thing, we aren't spending any time nor money to try and make that thing look good. It would only destroy the look and reputation of our company LOL