Hey, Jim. Sorry for the long response time, but I seldom ever check the old forum. We're trying to shut it down. Please go to the new forum and register.
By this time, you've probably already gotten an answer, but I'll still give it a shot. In this regard, the difference in the 87 and 88 is the width of the track at the front. The 88 hubs were moved out about 1 inch as compared to the 87. The rear wheels had the same offset as 86 and 87's.
To compensate for this, the front wheels of the 88 had centers that were flush with the outer lip of the rim. Basically they moved the centers of the wheels out, then moved the outer rim back in, to keep the same width track as the pr4e-88's. For this reason, you MAY encounter some scrubbing with aftermarket wheels on turns or during heavy braking. You may be able to overcome this by going to a smaller or lower profile front wheel.
Charles Sewell
President-Georgia Fiero Club