I know a lot of people on this board will be able to tell you more, but I can tell you a little.
Horsepower and torque were the same all years (93.5-98), no major engine or driveline changes.
97 and 98 offered polished wheels, standard on the turbo I believe.
I believe 97 and 98 were OBD-II cars.
Steering wheel in 98 was the 3 spoke design, not sure about 97.
Badging differed slightly through the years, notably the 15th anniversary emblem on the '97.
Taillights and headlights different on 97 and 98 (fronts darker and rears had different inner trim).
Earlier cars came with Bridgestones, later cars came with Michelins, not that it matters because most all of them have been changed by now.
The center console and door switch bezels are a flatter black on the 96-98 cars, the earlier cars have a glossier black.
This is all stupid little changes, I'm sure someone here can correct me if I'm wrong or add to the list. But this will get you started.
