If you want to increase the activity of the forums, the easiest way would be to add a 'Discuss' link to the bottom of the stories in, for example, the 'New Cars' section.
Create a new subforum for news items, and it would be simple enough to write a script which automatically creates a new thread, based on the headline and article that you already entered into your existing CMS software.
This would add another dimension to the news aspect of your site and bring a lot more people to the forums.
