MysticFreak, 1/4 inch over the max. mark shouldn't do any harm. If it were much more than the 1/4 inch then it could be a concern. I overfill mine using 6L of oil at every change. Specs call for 5.5L (5.8 qts) with an oil filter change.
I use my car mostly on the track and so I put the extra in to give it a little insurance against the dreaded - spun bearing from oil starvation concern.
Moderate overfilling used to be a concern years ago. IIRC, mostly because seals were made of poorer quality material and didn't like the slightly higher oil pressure associated with an overfill.
Regards, Alan
