I read in the anouncement for them that James said that the power output has not changed which leads me to believe that the differences would be less compared to the ST to SST which was a big leap in power and resolution.
Hi Bassmann,
I agree that power can be a factor.
In the SST to SST2 question, however, the sonic difference has to come from somewhere else. Just as I was surprised to discover that my 4B ST was clearly outperformed by my lower powered 9B ST and at least one user in this forum mentioned that he felt that his 6B SST sounded different/better than his 4B SST, although their mono channels are supposed to be more or less the same.
I would assume, that such a mono channel being in a compact module (as in a 9B or 6B) has its advantage signal path wise. On the other hand, you have less heat sink surface...
Anyway, there has to be something about signal path, grounding scheme, changed components and slightly modified circuitry that can make a huge difference that you cannot see in a figure like a power rating.
I am looking forward to the first user comments about the sonic differences between SST/SST2 too!
For me, however, being invested in SST 14B, 6B and 3B, an upgrade is very unlikely in the foreseeable future (I have to save a few bucks to get on the SP3 train...

whenever that train may start moving ...

).
Cheers!
Markus