TJ, 350 watts wouldn't be "noticeable" unless they were actually being used by playing louder. Since it's highly likely that the present amplification can already easily handle all safe(to your hearing)sound levels, playing even louder wouldn't be a good idea. Also keep in mind that the 140 watts would also see an increase into 4ohms to something over 200 watts.

My Denon 3808 pushes about 240W into 4 ohms according to a lab test that was done when it was first released, where is that link.........

Was that with one channel driven or both, Jay?

Both. Still looking for that site.

Found it here