I've read on the board many times about negative crankcase pressure. You should have a little difficulty taking off the oil cap when the engine running, or the engine should run poorly with the cap off. I experience nothing like that. The cap comes off easily with the engine running and the engine runs fine.

I'm burning a quart of oil every 1200-1300 miles. What does this sound like? Crankcase ventilation valves? Is it an easy DIYer, and do you replace or clean them? TIA.

I have replaced the whole PCV system to the updated one (yes BMW changed the system from the early models - new system will have white valve in the centre and air will be allowed through BOTH directions in the smaller check valve).
Still - my car runs fine (slightly rougher) when oil filler cap is removed, but definietly no choking or stalling.
I burn oil within spec and have absolutely NO running or idling problems whatsoever.

The moral: Checking for engine stalling upon removing oil filler cap would hardly seem to be a comprehensive engine condition diagnosis on such a complex engine management system.

My advice: if your car is burning oil within spec and is running fine "leave sleeping dogs lie" :)