Ebay? www.thecarepxerience.com ?Local races? F-ads? AMG/mercedes forums (www.amg-owners-club.com ; www.benzworld.org)? Porsche forums (www.flat6.net, www.6speedonline.com)? Just put the car (with good hi-res pictures!) in as many internet forums you can. There isn't that much demand for SL55 (they still are pricey cars), so you have to cover the whole damn country to reach all potential customers! Best of all, most forums or internet ads are free I've heard the Dupont Registry isn't worth it (while being specialized in high end). Just some thoughts...
I am sure there is someone on Ferrari Chat that would love to have an SL55 or at least knows someone who might be interested You could always put it on autotrader.com too. If the car is located in Michigan he could go through The Motor Car Gallery out of Birmingham. I believe they have a consignment program. Check out this link: http://www.themotorcargallery.com/consignment.html THE MOTORCAR GALLERY 394 S. Old Woodward, Birmingham, MI 48009 - Map 248-594-5940 Ph 248-594-3424 Fx I have never done business with them but maybe you or someone you know has. Hope that helps.