Consider this engine flush... Which has gained quite a few fans over on E46fantatics.
Attacks the oil control piston rings from both top and bottom.
Please see the flush in the link below. The author, MrMCar, was(is) a factory-trained, long-time independent BMW tech in New Jersey. He recently retired. He did this routinely for his M54 customers with oil consumption issues.
https://www.e46fanatics.com/threads/...n-fix.1335303/