Not sure if you've tried this one, but I've always had success with
www.craigslist.com. I sold my BMW this year courtesy of craigslist.com. In fact, if the price is right, I'm sure you'll have a large number of hits. I got like 25 emails in the first day. Just don't post your phone number. Although that's what most people will ask you for in their messages. Post a pic, too. Posted the BMW on a Thursday, sold it that Friday. The guy was even nice enough to buy my motorcycle too. And he paid cash.
P.S., people are shady, no matter what method of advertising/sale your choose. Auto Selling 101: Don't meet anyone at your house. I've run across some sketchy characters in my autoselling days. The last thing you want is some creep, whom you've just given an all access vehicle tour, to steal your ride while you're sleeping.