I have high mileage 335 AT which I bought with 60K miles 2 years ago.
The car gave me so many troubles I already regret I didn't get at least CPO with those miles.
So I would stay away from those cars.
EDIT: and I'm not talking about minor things here and there... I'm talking about as everybody say - turbo problems, carbon built up, leaking gaskets (head gasket, oil filter housing), etc, etc...
/ Was mich nicht umbringt, macht mich starker /