This list was started to document the running changes on 1988 models as problems were discovered and revisions were made to correct them. More items will be added to the list as they are discovered.
Most of the early 88 changes were likely due to the need for quality improvements discovered after early cars were sold and in regular use (like the added screw on the shoulder belt escutcheon as the snap in only one probably came loose frequently, or the elimination of the suede seat bolsters which wore quickly). I can see some of these things being missed during prototyping and very early build test units as they were not daily drivers so deficient parts and weak spots in the design may not have been evident yet.
Some of these things were strictly cosmetic, and the rationale may never be clear to us nearly 30 years later. Ones that were strictly expense reductions are fairly self evident.
- Upper shoulder belt escutcheon was revised twice, once to add a screw hole and second time to add an anti-warping reinforcement. The rear upper quarter trim panels in early cats also had an added mount point in the form of a plastic leg that had a single screw into the body sheetmetal. This was only visible with the shoulder belt escutcheon removed. This extra mount was removed in later cars as it appears to be superfluous and broke off the panel easily anyway.
- The light source for the optic lock cylinder halo on the outside of both doors was changed. On early 88's, there is a separate bulb holder for a 194 lamp clipped to the plastic wiring raceway on the door (behind the interior door panel). The fiber optic lead is routed to this lamp holder. On later cars this was omitted and the fiber optic lead was routed to the back of the red and white courtesy lamp housing on the interior door panel.
- The moving side window and rearward run channel inside the door were revised. Early cars used a tongue and groove type guide, later cars had a pivoting roller and rail type guide. This complicates replacement of the side glass on an early car as use of the later glass design will require changing the run channel as well. For the same reason, an early window will not fit a later car without using the early design run channel.
- The retaining system for the rub molding on the door exteriors was modified. Early 88's had pairs of studs welded to the outer door skin with plastic retainers having two key hole slots to slide into place over the studs. Later cars went to a single stud and the plastic retainers had only one keyhole slot. Note the early retainers could be used on the later door as the second slot would be unneeded, but the later design retainer with the single slot will not work on the early car having pairs of studs as the retainer will not slide and lock fully into position.
- The formed rubber over metal water guard cap on the hinge end of the doors was revised. Early cars had a piece that was notched out to leave the the two bolts for the vent window upper angle adjustment exposed. The later version covered these two bolts so that the water guard cap piece had to be removed (two self tapping screws) prior to adjusting the vent window angle. Additionally, this piece and the water guard cap on the latch end of the door was secured with T15 Torx screws on early cars and with Phillips head screws on later production.
- The emblem in the center of the horn button was a silver outline of the stylized R on a charcoal grey background, to match the anodized aluminum interior trim pieces on the dash and door panels. Later cars received a full color sunburst emblem much like that on the hood and wheel centers.
- The early build 88 seats had suede leather bolsters on the seat bottom and back, as well as the lower portion of the headrest. Interestingly, the suede trimmed seats had real leather for the rear facing portion of the seat back/headrest and for the side "skirt" around the seat bottom as well. When the suede trim was dropped, the rear facing surface of the seat back/headrest and the skirt around the seat bottom were changed to matching vinyl in lieu of leather, the balance of the seat upholstery was standard (non-suede) leather. This change to vinyl appears to have been a cost reduction item.
- The courtesy light and rearview mirror harness was revised. Early 88's had an additional wire to the rearview mirror which was grounded when the courtesy lamp were on. This enabled the map lights in the rearview mirror to illuminate in parallel with the courtesy lamps (overhead, footwell and door). This was eliminated in later build cars, but is easily added back in if desired as the rearview mirrors are all equipped with this third terminal on the plug.
- The black plastic cover that conceals the side mirror mount bracket were revised to be somewhat stronger somewhere after #1134. the difference is subtle, but my early 88 had a version that was molded just a bit different than any of my other cars or those I've parted out thus far. This is another case of a part that just didn't stand up as expected so an improvement was made. That said, the revised version really wasn't any better by what I've noted.
- Sunroof option was added after about #2500. (Padgett)
- Return for Teves was changed from rubber to metal after about #3500. (Padgett)