Greetings,
I have never understood why people suggest that changing the oil on a Box is difficult or requires special tools...neither is the case.
In reality, an oil service on my 2002 S is much easier than on my Lex GS400 or my GF's M Cooper S. The filter is right next to the oil pan. A small oil filter wrench or strap wrench makes it easy (don't over-tighten it). The drain plug is easily accessed as well. You need a jack, jack stands, a simple metric socket set and whatever you want to use to grab the oil filter (sticky rubber gloves would probably be enough to remove it by hand as long as it's clean.
If I paid $400 for an oil service I don't think I'd be able to sit down for a week!
Hengst filters are $14 on line and 5 qt jugs of the synthetic of your choice can be had for under $30.
My oil changes cost me:
~$30X2=$60 + $14 = $74 at the most, even if I figure my time at $200hr (time you'd spend in the dealer's reception area anyway) I am doing better than going to a dealership, plus I get to inspect the underside of the car.
It's really not a big deal and not beyond the capabilities of any healthy adult I've met.
Stop the bleeding folks, save your cash for real repairs...