The 4 litre BMW M3 is the purist's choice of DOHC 32-valve
racing engine for the Aquila CR1 - beautiful, sophisticated, light,
powerful, and high-revving. The CR1/M3 engine option is best suited
to classes with few or no restrictions as the M3 has considerable
tuning potential, and, due to its high specific output, it may also
be the best option for classes restricted by engine capacity. And,
oh, it sounds absolutely lovely, too!