We've had this recommended ever since the forums went live... and finally it's become possible.
Shahab, back on May 6th, 2005, soon after we went live with United Bimmer, posted this thread, requesting a choice of skins (especially a darker skin) for the forums: http://www.unitedbimmer.com/forums/thread826.html
In the development of United Subaru, I've realized a few things. First of all we've added so much technology to this forum that isn't normally there, such as the Rate-My-Car statistics under your avatar, the vbulletin skin engine wasn't able to change the skins anymore. We were locked on the white skin, and while it's nice, there was no more choices. The technology was now embedded into the site on a very low level.
In addition to all the work I've done recently on United Subaru, I've also created a brand new template system, written completely from scratch, encompassing all the technological additions we've already developed. This United Cars skin system has a central resevoir of templates that are made to be flexable and work with any number of United Cars sites... meaning when we create new brand sites, such as United Audi or United Honda (I joke, I joke), the skins can be instantly implemented without further modification.
You'll notice on your main horizontal links bar (under the banner top right) a new link menu: Change Skin. This will take you back to the forum index and change your session to the reflect the new skin. I have it set so when you close your browser, it resets, because the skin system is still somewhat in beta and the lighter color skin is the ony one completed. I've chosen to roll it own now because the darker skin is nearing completion, and only needs minor tweaks to smooth down the rough edges. In other words, it's usable. You'll notice a few of the smaller icons haven't been remade yet and clash with the darker background, but over the next few days you'll notice them slowly get corrected as I get to them in my ever-growing todo list.
Thanks for the patience of everyone who requested this so long ago, as we have many dreams, and limited time... we'll just go in order getting them done one by one.