Congrats on the 4806 purchase! This is quite an amazing piece of equipment and does take a while to learn all of it's features. I have been using the onboard amps and have not found their limits driving my M80's, I can't imagine what they sound like with external amps! With regards to the Audyssey upgrade, not all 4806's need it, only the earlier models. Mine did and it made a world of difference with my system. Installing the upgrade can be hazardous (to the unit), so if you do choose to go that route, be careful. The 4806 thread at AVS has a lot of information on this subject as well as many others. If you have the patience to wade through it, a lot can be learned. Have fun!!
