why not do it yourself?
i had a dealer who i HIGHLY suspect didn't do an oil change on my z4 before.
the reason i suspect this is that
1. they didn't reset the "miles to next oil change" counter - i understand you can sometimes forget but this leads to all other reasons below
2. at the time i brought the car in, the comp was showing 1/2 from max oil level, that didn't change when i picked up the car (it should have been at "full" or even "overfill") - thanks to BMW, that (N54 i think?) didn't have dipstick either
3. it was supposed to be the first oil change and the engine bay was pretty clean, no signs of oil anywhere like around the filter
so i'd just for my own peace of mind, would do 1 oil change in between myself JUST IN CASE they don't change at 15k miles
Future mod consideration: exhaust, pulley
otherwise, very happy with how the m3 was born