The NAD is great, but you get what you pay for. My first amp was a 3020 : it's a great amp, but a bit limited in dynamics, and with a slightly "fizzy" treble. When I upgraded to a Cyrus 2 integrated amp the dynamics and top end improved markedly. I bought that amp used for about $250 about 7 years ago. I think the NAD will be the weak link in your system, and you will not be happy with it in the longer term (however you'll be able to sell it on for the same amount of money, so this isn't a problem).
That said it's all about budget, and I think you'll have to spend considerably more than $100(at least $300) to get a big improvement in the sound. I don't think a newer NAD or Arcam (for around the same price) will sound much different. I think you'll have to jump to the next league (Audiolab, Cyrus, Linn, Naim Nait, bigger Arcam) to really notice a big difference in sound. Audiolab 8000As are about $350 used, and are leagues above the NAD, but they're 3 times the cost. The Audiolab or Cyrus 2 would be my choice (the Nait is a lovely amp, but overpriced on the used market).
If you do get the NAD there's a great tweak which worked well for me. Unplug the jumpers between the pre-out and power-in and connect the CD player to the power in. The sound was much more punchy (less warm and mushy). I have the same CD player as you and I know the volume resets to max when it's turned off, so you'll have to be careful. To me this implies that the NAD's preamp is the weak link, so I would discount using it in a pre-power setup later on. If this is not convenient then at least replace the jumpers with a quality interconnect ... that also helps, but to a lesser degree.
That said it's all about budget, and I think you'll have to spend considerably more than $100(at least $300) to get a big improvement in the sound. I don't think a newer NAD or Arcam (for around the same price) will sound much different. I think you'll have to jump to the next league (Audiolab, Cyrus, Linn, Naim Nait, bigger Arcam) to really notice a big difference in sound. Audiolab 8000As are about $350 used, and are leagues above the NAD, but they're 3 times the cost. The Audiolab or Cyrus 2 would be my choice (the Nait is a lovely amp, but overpriced on the used market).
If you do get the NAD there's a great tweak which worked well for me. Unplug the jumpers between the pre-out and power-in and connect the CD player to the power in. The sound was much more punchy (less warm and mushy). I have the same CD player as you and I know the volume resets to max when it's turned off, so you'll have to be careful. To me this implies that the NAD's preamp is the weak link, so I would discount using it in a pre-power setup later on. If this is not convenient then at least replace the jumpers with a quality interconnect ... that also helps, but to a lesser degree.