The BMW M54 is a naturally aspirated straight-6 petrol engine which was produced from 2000 to 2006. It was released in the E53 X5 and is the replacement for the M52.. The M54 topped the Ward's 10 Best Engines list in 2002 and 2003. The BMW S54 is the equivalent high performance engine, which was used in the E46 M3, the Z3 M Coupe/Roadster and the Z4 M.