sorry man you have no recourse, the image was not copyright, watermark, nor does it seem like you have enough proof to back up yourself. next time you want to post of photos of your ride you whould atleast watermark or post a copyright b/c w/o that you are shit out of luck.

you need to just drop it and be happy your car is being used on a site it will cost you too much in the end to pursue this and beyond that, that photo can be dr'd enough to where it won't even look like your car or they could just drop it at anytime... in the meantime you will have to pay court cost, legal fees, etc.