I currently have a dv-656a. Am thinking about getting a dv-45a. Think this would be a good upgrade? The two look identical, except for the colors of course, and the fact that the 45 plays sacd while the 656 doesn't, it does do dvd-audio though. What are the major real differences between these two? I wanna make sure that it's worth upgrading before I spend that much money on a dvd player. Thanks.