What do you think is lacking in the sound?
I did not notice a subwoofer in your post. Do you have one? Even though the Strata's are full range speakers, for movies and games a sub is definitely required. SVS, HSU, eD, etc. are internet direct brands that make exceptional subs.
If you already have a sub, upgrading electronics will only provide marginal gains, if any. Look into room treatments for substancial bang for buck improvements in sound.
Or is it the video side you are not happy with? Maybe, time to get front projection? Nothing wow's folks like a 120" screen

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