for the 17x8's I could be wrong, but I don't think the fronts will work if you want to have the center caps on, as the brake rotor extends too far out for clearance. If the center caps aren't an issue for you, they will bolt right up with a 5-lug conversion. But in order for you to do a 5-lug conversion on an '83 model, you will have to change over to an 87-93 spindle, or an SN95 spindle setup.
As for the 17x9's, they will work in the rear as long as the offset is correct. If you are using an SN95 axle, then they should bolt up w/o any problems in the rear. As for the front, like above you will have to change the spindle to something later model to get 5-lugs, and once you've done that, you will have to run a 235mm wide or narrower tire that is less than 25.5" tall, otherwise rubbing will be an issue.
I am getting ready to install some black 18x8 (front) and 18x9 (rear) ROH Drift R's on my '89 Mustang with the FMS 5-lug conversion rotors and axles. Tire sizes are 235/40/18 (25.4" front), and 255/40/18 (26.1" rear).