Miles so far - 4200
Driving mellow/agressive - 70/30%
Roads/highway - 80/20%
I've worked on engines, jet engines, lawn mowers, etc. And I've seen oil filters of high miles and low miles and let me tell you, there is a huge difference in the detereration of the filter element. I remember changing the oil of a buddy's '99 540i and the filter element was practically fused to the plastic filter center support housing. It looked like shit! On my Saab, I allways changed it at 3,000 miles and the filter's allways looked clean and that car has now 60K+ and runs like a champ. Saab recomends 15,000 mile oil changes. Ya, sure!
Change your oil about 5-7K miles if you value your M3. If not, get a GM or rice burner.