Thanks to all who replied! I wanted to add that the Onkyo 8511 has plenty of power (100 watts/140 peak). I did not specify what I was intending to upgrade to; I was considering the NAD C-350(60 watts x2), or the C-370(120 watts x2)Integrated Amp.. I listen to hard rock / blues rock, at moderate levels most of the time. I was given the impression that the 60 watt NAD would give me higher quality sound, and enough power for my needs. The C-350 was my most likely choice, budget wise. I'm looking for a step up in 'quality of sound'. I paid $295.00 for the Onkyo, and the NAD costs $430.00; I obviously don't want to spend that kind of money, if there won't be a great deal of improvement in sound quality. It is very confusing, when you read all these different reports, and hear different opinions. I just want to make an intelligent choice.
Any thoughts on my CD player; Integra CDC 3.1 ?
I appreciate your thoughts and information.

Danny