> What can I expect to go bad first?

If you don't know how old the tranny fluid is change it now.

They have a water pump with a plastic impeller. It's unlikely you still
have the original at 170k, so you may have the new all metal type.

> How long do these cars go for (given it was maintenanced properly)?

Forever :-)

> What is the best oil for the car?

Anything fully synthetic.

--
Who needs a life when you've got Unix? :-)
Email: , John G.Burns B.Eng, Bonny Scotland
Web : http://www.unixnerd.demon.co.uk - The Ultimate BMW Homepage!
Need Sun or HP Unix kit? http://www.unixnerd.demon.co.uk/unix.html