[garek]

IMO, whether or not the offer was a lowball or not, your response to the buyer's initial offer should have been something like:

1. Thanks for the offer, but that's much less than I am willing to sell the car for. (Politely decline the offer)

2. Thanks, the car has low mileage and is in perfect condition, $57K. (Counter the offer)

I actually agree with the buyer's initial response that in your response you were being a jerk. It was not a very mature or professional way to conduct a negotiation.

If you had been polite to the guy, you may have reached an agreement you both could live with. Instead, you just added to the stereotype that all M3 drivers are @$$holes.