I ran one ad in the DuPont Registy. Got 40 calls from all over the place, including Europe. Sold the car. More responses than all the other ads put together. Might be different now but I was impressed by the responses. Sure there were the dreamers and the people who couldn't affort an f-car, but I didn't have to meet them or show them the car. And, then, maybe I was just lucky (and was selling a great car!).
I have ran 4 ads with the DR in the last 4 years. 3 out of 4 sold within in a week of the issues coming out. I got what I was asking for 2 of them....and $2,000 less for the other one.