Ray,
I suggest that if you want more power, do not switch out your 1803 for a 3803. The increase from 80W to 100W per channel is relatively insignificant. If may provide anywhere from 2-3dB more in actual volume and that's about it. Someone did the math around here awhile back and i believe Alan did the same in one of the Axiom monthly newsletters.

Unless you are interested in the greater number of channels, connections that the 3803 offers, you would be better off increasing your 'power' by running your main speakers off of a separate stereo amp.
It would be alot cheaper than buying a 3803.

"Those who preach the myths of audio are ignorant of truth."