Is King Of Fighters Maximum Impact maniax different from Maximum Impact and Maximum Impact 2/2006 from Maximum Impact Regulation A?

I have KOF:Maximum Impact 1 and 2 but these ones confusing.
I know a little about Regulation A that it don't have story mode but have extra characters like Blue Mary.
Do Maximum Impact Maniax have story mode?

Shall I buy Maximum Impact maniax & Maximum Impact Regulation A or not?

I will like to know if there are graphic improvements in maniax and regulation A.
I don't care about 2-3 extra characters.

(Sorry if I made any grammar mistakes)

based upon what wikipedia sez its basically and enhanced port of the first game and since wikipedia does not say anything about difference's between the original one I am guessing its just the same game with a few more stages and enhanced graphics or somesort does not say anything about extra characters