If you plan to do high volume, low margin sales to buyers in the know, make sure you partner up with some of the auto brokerage businesses. I'm sure it eats into your profits a little for the referral fees. But not everyone goes directly to the nearest dealer's website to shop for a vehicle. Many will go through a broker like autobytel.com to locate a sales department in the vicinity (radius search) that will treat them well.
Also,
- lots of pictures of the products and facilities
- easy access to contact / address info for the various departments
- good directions/maps linking out to the big map sites to make it easier
- direct access to sales people, service writers, and managers (post phone numbers and offer email). Just make sure that these individuals will actually read and respond to the email or answer the phone in a timely manner
- If you run events, some kind of active news area, e.g. do trip reports HUMMER Happenings. This is a good way to let people who networking see that your site isn't stagnant and find out about events without having to send fliers/invites out to all your customers.