The base C4 sold for approx $34,000 , the ZR-1 option basically doubled the price of the car, List Price in 91 was $67,013
There is very little to distinguish the ZR-1 from the base model, the high mount 3rd brake light and the fatass rear end, noticeable by looking at the rear license plate. There is approx 2 inch gap between the license plate and the back up lights on each side on the ZR-1, the base model does not have this.