Miron.
I have the Denon 3802 and it is matched with the Synergy speakers (SF1, SC1, SS1, KSW12 and old Koss speakers for the second set of surrounds).
The whole thing sound great and I would not hesitate to recommand it to anyone.
The Koss are rated at 40W. Since I use them for surrounds I haven't have any problems yet even when I pump up the volume. So you shouldn't worry about 10watts.
Luke.