I replaced a Pioneer Elite receiver from the same general vintage as yours with the 990 and a multi-channel amp. First, I connected the Pioneer to the amp and gave it a good listen thinking that the pre/pro part of the receiver would be OK so I wouldn't need to purchase the 990. There was an obvious improvement with the amp and Elite over the Elite alone but there was no "Wow" factor. When I put the 990 with the new amp I knew almost immediately the Elite receiver was going to ebay. The 990/new amp combo sounded so much better when using it for HT than the Elite alone or with the new amp. Subsequently, I've grown to really like the music reproduction via the 990 and my listening habits have switched to more music than HT.

I can't speak to the Denon but I'm pretty confident you will notice an improvement over your Elite receiver/amp combo when you use the 990 to handle the pre/pro functions. Just my 2 cents.