As Drew recommends, we've been tempted now and again to switch across to the E39 M5.
It needs to be low Kms to feel sure that you can sell it easily later on, as you Bobby concur.
We bought this 530i Individual (2003 model) for $28K back in 2009 with only 48,000Km.
It's now done 79,000Km for an 11 yr old car. We decided to keep it for a while yet.
You're welcome to test drive her (without being considered a tyrekicker).