81k miles for a BMW, particularly the 3-Serie, is really not too much. In the familly we have a 2000 323 with 87k and it runs and looks like new. However, you have to expect and accept some little issues to occur like for example windows regulator or A/C final stage resistor to be replaced. I would suggest to get an extended warranty with it if possible as with BMW all these little things can add up quickly.