Maj, the question should be if there's an actual technical reason to go "bigger/stronger". The answer is likely to be no, since the 3808 should have plenty of capacity to power those speakers at safe listening levels and beyond.

If, as you say, you want to stick with Denon, you won't be able to get anymore than a very small and audibly insignificant increase in maximum power capacity.

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Enjoy the music, not the equipment.