I'm in the process of re-doing my living room, which involves upgrading my AV setup as it's a bit of a mis-mash of products. My main concern in the amp. I have a Marantz SR5200 and i'm wondering if upgrading to something like the Yamaha DSP-AX763 would be a significant enough upgrade ? I've just bought the Tannoy Arena 5.1 speaker system and intend to play mainly DVD's and audio CD's. No real urgency to go Blue Ray just yet. I also was considering the Nad Viso 5 as it's everything on one box, but is very costly ? Is the Marantz too long in the tooth, or is there life in it yet ? Cheers.