How can I verify that this business is legit?

So I am planing to purchase a new car and so for added research, I joined a popular internet forum dedicated to that car. Here I was contacted by a member on how to get that car for a better price through an out of state dealership. Apparently over 70 people from the forums ordered their vehicles through him. I am still a bit skeptical about it all. Is there any way for me to verify the legitimacy of this establishment?

Thanks.