When my car was almost about 2 weeks old I had some leaking around the oil cap. I bent the retainer arms on my cap ever so slightly to put more preload on the gasket, never had a problem with leaking since!
2011 E90 M3 ZCP - Individual Moonstone/Individual Amarone Extended/Individual Piano Black With Inlay:LINK!!!
1994 Euro E36 M3 Sedan - Daytona Violet/Mulberry:LINK!!!