Starting in September 2001, the engines were upgraded to the BMW S54 engine from the E46 M3. In most countries, it is rated at at 7,400 rpm and at 4,900 rpm, while North American models have at 7,400 rpm and at 4,900 rpm. The difference in peak power and torque is due to the catalytic converters being located closer to the engine on the North American spec cars, which allows the catalysts to heat up faster and reduce cold start emissions. A total of 1,112 cars were built with the S54 engine.