yeah they'll fit, loads of mustang seats fit, i kinda like the slimmer seats from the 2000 model, just be sure to get some seat belt buckles unless you want to use the originals from the bench seat which will be floppy. the mustang buckles are covered in a stiff shell to keep them upright, the buckles from an 89 should be direct fit to the 80 model seat belt retractors.