[Boss 5.0]

I'm curious, and forgive me if this seems like a really ignorant question, but what are some of the major differences between this and their top of the line chassis?

So I have a 55 Chevy Bel Air, why would I order this Spec series vs their higher priced chassis? Clearly for the price drop something is different.

I like what I see, and I really like the price point. This makes a chassis swap more attainable for me. I'm just curious on the differences.

Thanks