Sorry, I typo'd. I meant to say that they should move away from the cross-plane design.

These M engines are supposed to be about maximum performance, so I don't understand why they used a cross-plane design. Reducing the counter-weight size would do wonders for engine response, and it's also proven that a lighter rotating assembly yields greater power/tq as the rpm go up. And let's no forget about the packaging and performance benefits of a more compact crankcase that a flat-plane design allows.

If the 4.0L V8 used a flat-plane crank design, it probably wouldn't even need balance-shafts to counter the second-order vibration. Usually 2.0L is the cut-off for 4cyl's, and a V8 produces only 41% more second-order vibration.

The Formula One V8 most certainly uses a flat-plane crank. Why not the M3?