I wouldn't bother. You do not have the car anymore, how are you going to prove your case? It's your word against theirs and they can afford better attorneys than you can.

 

If it comes down to it, the court recognizes the certified mechanics as "experts" despite what you may know of their abilities and technical knowledge.

I bought a 240sx a few years back for $5400 from a used dealer (not a name brand dealership). The car was certified for safety (by the dealer) and emissions tested, etc and I purchased a third party warranty. 5 months later I discovered that the frame rails were completely rotted out. I paid a local safety certification shop to assess the serious problems with the vehicle, wrote reports, had affidavits from experts and a chemist that the rust holes could not have occurred in that 5 month period.

In the end the judge found in favor of me, but then turned to the dealer who had scammed me and asked what the car was worth right now. They said "It's all rusted on the frame! Maybe $1500?" and that is what the judge awarded me. Mind you I got to keep the car and sold it soon after for $2000 so in the end I was out a couple grand.

Court found in favor of me and agreed that the dealer was fraudulent and lied, then relied on them to be honest when their honesty was about to take money directly out of their pocket. Very nice.

I would expect something similar, and you should probably let this go. Bad dealer, never go back and warn other people as well. You could always go the route of parking a car in front of their dealership with big signs and a description of how they scammed you without getting in trouble. As long as you just tell the facts you will never get in trouble for "defaming" them. Facts is facts.