What’s the best DAC match for the Cambridge Audio CXC original or V2?

Agree w/ others. There's no matching question here. It's a question of the kind of sound you're looking for and the way you achieve that given the various factors in play in your room, system, etc.

That said, here's my experience: I have tubes -- tube preamp, amp. I don't want over-coloration but I want dimensionality and accuracy but not too aggressive or forward in the upper mid, treble.

I bought a CXC transport and tried it with: an Audioengine D1, a Peachtree DAC*IT, and an MHDT Orchid Dac. The Orchid was the best, and got even better when I rolled a Tesla tube into it. I did comparisons of these (relatively inexpensive DAC's) against the Orchid and the difference was significant. I have heard many good things about the Tubadour III, also. But that's really the limit of my experience. I would bet good money that if someone plunked down other good Dacs in my system and blindfolded me, I might not really know what to choose; but against the less expensive DAC's I owned, the step up (to the Orchid) was a real advance.

A not-unrelated question is this:

Of the Dacs which meet your (a) price point, (b) possible sonic preferences, which are (c) available to try out in your present system? As many point out, it's very hard to make snap judgements about audio. It helps to live with something for a little while. If you had two Dacs which were both reasonable candidates, get them both into your home on trial and take some time listening to them. It's better than buying quickly, selling, buying again. Just a thought.