Any Benefits of a DAC vs a one box player?

I have recently moved and totally revamped my system. Much smaller room, new cables and speakers, new cd player. My new room is 17 x 20 with a 9 foot ceiling.

I have recently added an Audio Research CD-2 to my system and I love it. Would adding a DAC and using the player as a transport improve much? There is an Audio Research DAC-5 currently for sale here on the 'Gon.

My current system is:

Audio Research LS-10 solid state preamp
Audio Research CD-2 cd player
Infinity Reanaissance 90 speakers
Sunfire Signature amplifers (2 of them, one per speaker in a vertical bi-amp configuration)

Signal Cable Silver Resolution Reference XLR interconnects
Signal Cable Silver Resolution Reference Speaker cable
I was just told that the Audio Research DAC-5 is old technology. Will $500 worth of DAC make much of an improvement here? Will $1000 worth of DAC make a marked improvement over $500 worth?
I'd bet that the internal DAC of the CD2 is better than the older external unit. You have a nice system. I'd save the money and upgrade your amps.
340-square-foot listening room with a 9-foot ceiling--nice! It is my understanding that the DACs in the CD-2 and the DACs in the DAC-5 are the same DACs. If one reads the product literature on these 2 units, they appear to be the same equipment. One could telephone Leonard or Chris at Audio Research and attempt to verify this. I have never bothered to do so. I have owned both a CD-2 and a DAC-5 and I believe them to have the same internal DACs. My ears tell me that if you drive the DAC-5 with a quality transport through a quality AES/EBU digital interconnect that you will get a slightly better sound than the CD-2 alone. But Mitch, I would not sweat the small stuff; if you like your CD-2, just enjoy it!