What should my pressure be? Make Model Spec 911. 3.6I, 3.8I CARRERA 4/4S COUPE, CABRIOLET911. 3.8I CARRERA 4S COUPE, CABRIOLET911. 3.8I CARRERA. 18 WINTER TIRE911. 3.8I CARRERA. 4, BASE COUPE, CABRIOLET911. 3.8I CARRERA 4S COUPE, CABRIOLET911. 3.8I CARRERA. 4S WIDE RIM911. 3.8I CARRERA. 4S, BASE