On my '86, I had to cut the fender in an arc from the body trim down with about 1" at the bottom. Plastic trim would not fit unless I cut an inch out or used the 91-93 LX pieces. I also run the "zero" off-set arms and about -2* camber. With 17x8 et-36 with 255/40s and no fender rolling, I had no fender rubbing at the peak, at the inner or at the cut. However, when I mounted up my 95 Cobra Rs (17x9 et-26 with 255/45s), those rubbed the fender at the peak. I was already running a lot of negative camber so unless I wanted to run more or raise the car (then at 25-3/8" ground to lip), I'd need to roll the fenders. I ran more camber and raised it to about 25.5". That worked for my needs.
Keep in mind that the earlier fenders are longer at the extension area - about an inch or so - over the 91-93 fenders. So if you have an earlier model you need to compensate.