The digital-to-analog conversion in the DVD player is probably the weak link in that setup. If you intend to stick with CDs as your source, then a disk player with better DAC might make sense. You probably have to spend north of $500 to really hear an improvement though. Oppo BDP-95 is a popular choice, Though a little spendy, it would give you a little room to grow your system.

These days, I prefer a laptop/external DAC for source. It opens up the possibility of hi-rez audio file playback, and can help manage large music libraries. There are a lot of equipment options with this route, but if you have the computer already, then an external DAC doesn't have to add too much in cost.

As to cables, I don't know what you are using for speaker cables, so I have no idea if Rocket 33 cables will help or not, but if you are already using appropriately sized cables with low resistance, then I would put the money towards a DAC or an Oppo (or another) player.  For a 3' pair of RCA interconnects, I would pay up to $50 if I wanted to splurge.

I'm not really sure what you mean by wireless DAC. Do you have an example?

To select an external DAC you basically need to know how many, and what type of input(s) you'll be using. USB, S/PDIFF, Optical? If you'll be using USB only, one of the smaller portable USB powered DACs might work. As a very rough guide, I think a DAC costing about the same as your speakers or amp would be in the ball park. jackfish should be along any minute for specific equipment recommendations  :)

Is your speaker wire 16 gauge each conductor, or 16 gauge equivalent circuit? I usually go for 14 gauge or thicker, but if under 10' 16 gauge can do. Bi-wired with 16 gauge conductors would be good I think.

A good CD player will make a huge difference, now that you have good speakers and amplifier (are those T6 or B6 speakers?).

The OPPO BDP-103 is what I would recommend. It is $500, and there is not much in that price range that is going to come close to its sound quality.

The OPPO BDP-105 is SOTA, but $1200 is probably not what you want to spend.

I am selling a set of bi-wire Audioquest Indigo speaker cables for $150 if you are interested.

They are not made anymore, but would probably retail for $900 or so if they still made them.

See my ad in the classifieds at AVS Forums.