My 2 cents says make it for gold members only unless approved by the moderator.This way if members are selling a non Mopar it might just help someone or two of us out by having this for forum to maybe pass on a deal or whatever.
This is what I do on my website, but for a different reason. We were getting a lot of people getting ripped off by first posters who claimed to have something to sell, collected money, and never sent the items.
Once I made it so only paying members could post forsale ads, the ripoffs stopped completely. I believe the reason is that once they have to pay through PayPal they have "skin in the game". At that point they are no longer anonymous, and have spent a bit of their own money for the privledge to sell.
It did upset some of those who never wanted to become a paying member ($20 a year), but the fact that we are not seeing the ripoffs that we used to makes it worth it in my eyes.