I always thought it would be kind of nice if each model also had their own selling section. So if someone has JK items to sell he/she would put it in the JK for sale section. That way I don't click on something hoping it's for a JK and come to find out it's only for a TJ, for example.
Just an idea since you're making changes to the site. I like what I'm seeing so far! Keep up the great work!