You've got to have a website ! thats your shop front regardless of how many cars you have , people need to know all about you / your business etc ! And you'll also be amazed at how many keep an eye on your website for new stock arriving to buy for themselves or recommend others to your cars/website !
Yes, it'll add value and legitimise your business, customers will search for your website. I use CarDealer5, they're websites are excellent value, easy to use and I can highly recommend them in every respect.
Hi
In another business I tried this and found that's it's massively time consuming to try and get your garage any where near the top of the google search without spending money on google adwords etc
best bet is fscebook I think spreads quickly, I know someone that had over 5k genuine followers/likes he just offered free things to share it for instance win free full valet costs you next to nothing but will get shared quickly and easily and do pics of the fee valet with customer win win and not very much outlay
hope this helps