I bought my 99 on eBay last year. I live in Ca., and the seller lives in Dallas. It was his wife's car. The transaction went as smooth as butter. No complaints. Bought a great car! I really have no recommendations or advice, except to be leery of sellers OR bidders with (0) feedback.
Take lots of pictures. Get a large enough deposit at the end of the sale and payment in full when they come to pick up the car. Ebay buyer are looking to pay way less than wholesale so keep that in mind when you set a reserve. Watch a few of the Ebay auctions first for the same model and options to see what they are going for. Write your ad to compete with the other ads for the same model and features.
There's been a lot written on how to get the most out of ebay. E-Klasse is right about the pictures. Point out that you are not a dealer and you're selling your personal car. Explain in loving detail all the care attention and garaging you've been through to keep it nice. It should sound special. Make sure you respond to the questions you get and allow them to be posted.
A lot of give and take will help the numbers. Look at some of the other non-dealer ads you like and learn from their verbage and style. Pick one that matches you.
It goes without saying but -- the used car market is soft right now. I have sold a lot on ebay -- and bought my W210 from an ebay dealer, but the best numbers right now are from a quality 4 or 5 line ( not 2 or 3) ad in the highest circulation local paper. In the LA Area it's the LA Times, for example.
The Edmunds(dot)com website has a great forum for setting realistic used car prices based on current market trends and locale.
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