the 54 does everything the 56 does minus the firewire, the usb, the phono pre-amp, and the lighted remote. There may be one other thing I am forgetting, but essentially the 54 and the 56 are the same. You can even bi-amp your front channel speakers in a 5.1 set-up. If you don't need the extra connectivity, backlit remote, and the phono input, definitely go for the 54.