I have to admit that until I purchased my 2008 Challenger SRT8, I felt the same...big deal...anyone can "buy" a new show car. But, that all changed when within a month of purchasing my Challenger I enter an All Mopar show and won my class (stock Hemi, 2003-present)...I was hooked! I have since enter "open" car shows that had all makes and models and my new Challenger has always been well received. It's a lot of fun to talk with car people, and the new Challenger always attracts a large amount of attention.
Be sure and have some type of "information board" (or at the very least a copy of the window sticker on the dash) for people to read, and learn more about your car. In many shows, it's how your car is presented that can make the difference between winning and losing. Just don't go overboard with the displays, as this could draw their attention away from the car itself. (Forget the angel hair displays from the 50s and 60s!) And, bring cleaning materials to the show to keep your car looking good (and yourself busy). Along with cleaning materials, don't forget a chair and some refreshments for yourself, as most shows will last the better part of a day (and you have to stay until the end if you intend to pick up your trophy). These are just a few ideas, I am sure others could give you more, but the important thing is to "just get out there and do it"...it's a lot of fun and you will be surprised at the number of new friends you will make, perhaps even a few Mustang owners....
(Got to go...getting ready for a weekend show...)