TomK said:
According to BMW's workshop manual that's not true (and also what I've been told by my shop), no run in period is required for these on replacement. I think most just take it relatively easy for a few hundred miles to be on the safe side, 1k is unnecessary.
By BMW's workshop manual you're referring to TIS/ISTA? I couldn't find any reference to it and unless it specifically says that a run-in period isn't required I wouldn't take it to mean that it isn't.
I know the arguments which say that the break-in is unnecessary, but it is recommended by BMW: under SIB 11 04 04 (rod bearing updates for early E46 M3s) it specifically states that a 1200 mile break-in period is required following the correction work. I have two friends who are experienced BMW techs, both E46 M3 owners and they agree that a break-in should be performed.
That said, I do agree that 1200 miles of break-in is certainly overkill but dyno runs are not a casual engine operation so I definitely wouldn't be doing one too soon after the bearing change!