BMW Freak,
I have an 05 545i that I bought with 80k on it and wondered the same thing.
So i called around and found an honest shop here in Dallas and he said nothing last forever hence the sealed forever transmission. So to protect my investment it cost me a little more. About 800.00 more but that is cheaper than a transmission down the line. You may not have to pay as much, here is where you may get lucky. It has 2 types of pans metal or plastic that cannot be replaced after it has been dropped. Both have the filter built in. If its plastic it will cost 300-400 hundred. That's why mine was 800.00 I have a plastic pan. With all that said I totaly feel it was worth it.
Bobby