Do you feel better now that the ad you posted has been cancelled/deleted. You say you don't want to report anyone, but you post their ad in a public forum and call attention to it.
You also say these car dealers play by a different set of rules, but has it ever occurred to you that they may be selling many different types of cars and occasionally they come across a replica and sell it so it slips by the Porsche police.
I don't know what else you sell on ebay, none of my business, but is it possible that since you always sell one "type" of car, that your ads are automatically flagged because the lawyers consider you a commercial seller of their product,versus a person who might sell a one off?
I don't know you and I am not trying to be a complete as.....e, but it gets old reading you whining about the same problem over and over.
Maybe it is time to try something different that may get you results, instead of repeating what you have been doing and coming on here and bitching all of the time.
Sorry for the rant, just my 2cents.