Hello All, I need some good advice for a receiver upgrade. I currently own a sony db-840 which i`ve had for a couple of years. It has served me well and it sounds pretty good,but i`m looking for something better. My budget is 600-700 dollars. Is there anything in this price range that will give me a noticable improvement over what i already have or would i have to spend more ? My speaker setup is klipsch sf-2,sc-1 and ss-1. So far i`ve considered: denon 2802 marantz 5200,6200,7200 Would these fit the bill? Any input would be greatfully appreciated,thanks.