I currently got the 550 package hooked up to my sony bravia, but i am fancying moving upto an upscaling player. I was thinking of either the 2930 or 1930. I started to flick around on these forums and saw people talking about the 4306 reciever. What are the differences between using a reciever and not? I thought i could just use the 1930 or 2930 straight into my bravia? Why would i fork out for a reciever?