The S54 absolutely had rod bearing issues. There was a recall on the 2001-2003.5 M3s to replace them and BMW switched to 60w oil as part of the remediation. They’re still having issues to this day.
The S54 is also notorious for VANOS issues and cam drive failures. I had to replace the solenoid pack on mine but elected to not upgrade the drive while I was in there.
The S54 is also notorious for VANOS issues and cam drive failures. I had to replace the solenoid pack on mine but elected to not upgrade the drive while I was in there.