My 540iA M-Sport does 2,000RPM at 110kph. But it's a bit different than a 525iA.

And I'm looking to do the opposite. Not sure what's in my diff right now. Would like a 3.64 or 3.73. But I do have that 3.91 from the earlier US E34 M5. Too bad it'd be hard to find someone with a later US E34 M5 that's got the 3.73 and wants a 3.91. That'd make for a nice swap.