18 inch wheels on an 88?

You'll probably rub up front but in the rear i think you would be fine... Maybe need some harder springs to keep from bottoming out. I have never seen one with 18's on it but I am just assuming. I love to see pictures though if you do it.
 
had 18x9s on my 87 lx and my 90 gt, 245/40s and 255/35s, no prob with either, the lx needed +18mm and the gt used +24mm. just get the correct offset for YOUR car. all stang differ alittle.