Congratulations and welcome to the club!
Before too long you will realize how truly wise Rwwear's words are, heheh. For us respondants, it's already way too late!
Is there a specific area "sound wise" you'd like to improve? What do you feel is lacking? Answering this will help people to offer suggestions.
Also, I'm a little confused on your use of the terms digital and analog interconnects, because it seems you're thinking they're interchangeable when they really have different intended uses. Correct me if I'm wrong.
As Chadnliz suggests, if you're using a digital interconnect between your changer and Marantz it should only be a single cable and then you'd actually be using the DAC in your receiver and not the one in your CDP. On the other hand, if your using an analog interconnect pair that would mean they're connected to the analog outs of the changer to the receiver and in that case you'd be using the DAC in the CD changer.
To be honest, in your case I wouldn't know which DAC is the better one, the Marantz or the Pioneer. I might guess Pioneer. Before you go out and start buying new equipment you might want to try the different hook ups between your changer and receiver to see which you prefer.