Welcome to Axiom. What you've heard about "better sound and clarity" is almost certainly wrong. If your present receiver isn't being operated at an extremely loud level(dangerous to hearing)which exceeds its designed power limits(unlikely), spending money on a unit with a still higher power limit can't improve "clarity". This is the situation regardless of whether the amplifier is inside a receiver or is a separate unit.

If you want new features, consider a receiver that has them. A higher maximum power limit in a separate box is about the least likely change to be helpful.
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Enjoy the music, not the equipment.