This concept seems to have been imperceptable (or not?) to the Japanese receiver/preamp makers for the last 40 years. Yet, North American products (higher end) often allow for upgrades. Now, finally, Denon has realized that maybe (due to the diminishing U.S. middle class) a $3000 receiver shouldn't be obsoleted every 9 months. Denon's top of the line receiver (a year ago) can actually be partially upgraded with a $1000 board (installed by Denon service reps) so that it is "close" to the level of the latest $4000 behemouth. This is a good sign. The Japanese are facing reality; If you want to charge $3-$4k for a receiver that once would have cost $1500, you have to allow for some flexibility and longevity. Lets hope other Japanese designers/companies realize this too.