Floorstanders?

Hi, i am looking to change my current standmounters(Dynaudio Contour 1.3 mk11) for some mid sized floorstanders. I have fell in love with the look of Monitor Audio's Silver range knowing that i would probably have to increase to the GS range to get a similar level of quality.

Is there much of a difference between the RS6(£600), RS8(£800) and a jump of £700 to the GS20?

Musical Fidelity A3CR power / pre amps & A3 cd player

Chord company Odyssey & Chorus cables

Thanks