Do I want a preamp?

I would reiterate everything Kana813 stated but also add amplifier gain as a factor. If your amp has less than 30db gain you should keep your preamp.

FWIW, I currently run my DAC direct into my power amp and it sounds wonderful.

I have the Cary 303/200 CDP, and I prefer to listen to it through my ARC preamp. The sonic difference is subtle: slightly warmer and more involving. I might mention that before I rolled the tubes in the preamp, the difference was more or less negligible. I agree with Kana813 -- call Cary. Also, there have been some previous threads on this topic that you should take a look at.

You absolutely want a preamp if your budget allows for at least $4.000. for the pre alone. That's what it will take to better a CD direct or with a passive volume control. Anything less and it would be better to buy a better cd player and go direct. Once you get up to the likes of Herron or Hovland or cat etc. it is no contest that the pre adds dynamics and life to the music that no passive setup can match. Don't listen to the idea that less is better because the digital volumes are crap. and the analog volumes are still a filter in the signal path with a input and output impedance that affects the end result just as much as an entire active preamp!

I wouldn't be as dogmatic as Mahandave. My own experience is the observation that my accuphase cdp sounds much better through a Placete passive than direct to the amp or through a BAT vk5i (a 4k preamp). Try them all and use your ears. Good luck.

I agree, Msa. here's no question that my Aleph 2 monos are much happier having an Aleph P pre ($1800 used) pushing them rather than direct from my EMC-1 MkII (balanced).
It all depends upon gain and impedence matching, which can be a huge problem when going direct from a CDP to a power amp. Good luck.