I'd tend to agree with Cheesebert, if you can wait. I thought the 3.0 IS available now (may be wrong, though), but what I'd wait for are some reviews on it. It also foregoes the headphone amp, which may or may not be a good thing if it fits your needs.
If you want ot go for the 2.5, it has GENERALLY been agreed upon here that the core DAC with the CS chip may be better liked than the core DAC with the AD chip. I say "core" DAC meaning the basic DAC, with perhaps some of the upgrades you mention (caps, etc.).
If you're considering going all-out on mods, and replacing the output stage with a Zapfilter or Oritek mod, then it is GENERALLY agreed that the AD chip may be better.
I think if you look through the long series of posts, some folks have classified stock AD chip as being a little leaner and detailed sounding, while the CS chip a little warmer and fuller sounding.
Based on the comments pre- and post- output stage mods, I would think that the existing output stage may mate with the CS chip a little better for most peoples' tastes.
On a very personal level, I like the stock DAC with CS chip. I put LM4562 opamps on the stock output stage, and bypassed the DC caps, and had a very good sounding DACfor the $.
But, I moved on to two Oritek DAC's, and they are clearly superior. Cost twice as much, but worth if IMO if you can afford it.
Hope this helps....just my opinion, and my interpretation of what others have written. Still worth checking out the thread if you can get through it