Modifying a supergun

everyone is always saying that Sigma makes the best supergun...
i assume its because they use a better RGB convertor than, say, MAS systems
am i right?
could you buy a better convertor and swap it by opening the MAS systems unit?

If your using the same kind of weak conection instead of rgb like s-video,would the visuals be the same?

If your using the same kind of weak conection instead of rgb like s-video,would the visuals be the same?