I am working on getting Mustang Evolution more tightly integrated into Facebook. I can't tell you all the features yet but it will be pretty sweet.
Hopefully have this all up and running by next week and hopefully it will bring a few more people in and get the site some more exposure
P.S. I can tell you one feature: People not currently members but have a Facebook account can click one button and register without filling any info in. Basically you can register and sign in with your facebook account for new users.
Current members can link their facebook account with their MustangEvolution account.