[The Wind Breezes]

So I did some calculations and it turns out the mean piston speed in a N54 / N55 is very close to the S65 / S85, as those M-engines trade stroke for RPM.

S65: stroke 75.2 mm rev limit 8,400 RPM
MPS = (2* (75.2/1000) * 8400)/60 = 21.05 m/s

N55: stroke 89.6 mm rev limit 7,000 RPM
MPS = (2*(89.6/1000) * 7000)/60 = 20.90 m/s

So why is there all this hubbub about rod bearings in higher mileage S65 / S85 engines, but not as much discussion for our engines? I will provide a few guesses off the top of my head, but I'm looking for informed opinions as mine are only amateur speculation:

1) S65 / S85 have been around for longer, so more examples have reached high mileage (maybe really marginally longer in the case of the S65 vs N54, though...actually, which was out first?)
2) On average, owners of S65 / S85 cars are probably more likely to do track days or other high impact use
3) S65 / S85 need to be revved high to make power so they encourage use at high RPM, N54 / N55 don't encourage this as much
4) Maybe S65 / S85 pistons are slightly heavier as a result of the larger bore? I have no idea if this is the case or not. What about the weight of the rods?