If you are an insider, (such as a GM employee or a supplier in the case of this forum), it is in your best interest, and the best interest of the forum to be careful what information you post.
While it is not likely that participation in an enthusiast forum is prohibited, usage of the internet from work may be restricted, and it is likely you are not free to post "anything you want".
This is especially true if you are considering posting information that is considered "confidential", such as pictures, project or program information, marketing information, driving impressions, financial information, and the like - i.e. things that are not readily available to the public - things that can constitute a breach of information security.
Security info breaches really do no good for anyone. Information leaks hurt competition, are many many times inaccurate, and can ultimately result in the crippling or shutting down of a website, with corresponding draconian measures from the company point of view (like blocking access to websites - which would prevent folks who really need to see the information discussed from seeing it except from at home).
So, post responsibly, do not post anything that can be considered "confidential" information, and if you have "insider information" that is not available to the general public or available to everyone in the public domain, you should keep it to yourself - while we all want to know the whole scoop, it's not worth your job, or the hardship that could result.
Included is a link to an article that may be of interest - a case where a K-mart employee was fired for posting financial information on a forum: