Autotropolis is one of the best 3rd party leads we get. I am currently in the process of adding their SEM program. They are great to work with and their leads are awesome. The only problem is I can't get enough from them. I'm excited about their new SEM program and if it is like their other program, it should be great! I'll keep you posted.
Check out their website at http://www.autotropolis.com/dealer/