OBD2 cars are much harder to tune/extract power from than OBD1 cars, hence the less hp gain for the later years.
Also, for the 95 cars, a simple chip replacement is used to bump hp.
As for 96+, a flash of the ECU is required, hence the higher cost. __________________
318Ti Sport (Gone, but thanks for your years of service) | M3 E30 | 190E-16V | M Coupe E36/8 |