Well, well, well...
I have heard the Double Impacts. 3 times already, in fact! None of those times were in optimal conditions, e.g. my own room, setup the way I want them, with my Linn KDS/3.
However, with the exception of some non-upgraded Double Impacts, the upgraded model is quite a treat. The imaging as good as anything out there, but in both instances the front ends were not all that great, and one was in a home theater setup (without the center channel activated, of course). That's not a dig on the people's gear; i'm just saying the conditions could have been better. In one system, though, I remember thinking, "This is like having Sennheiser HD800s in speaker form." Take that as you will, because this particular setup had the speakers about 12ft apart, while it is recommended that the speakers are set about 6-8ft apart. In other words, the imaging was quite strong, but anything panned left and right sounded VERY left-right, with a slightly recessed center. So, yeah, too wide of a soundstage.
Otherwise, I'll have to get these in my own home to really put them through their paces. I went for broke and ordered the mini-Ulfbehrts, with a 60 day trial, so either I'm out $300 for return shipping, or I have magnificent speakers. It's a win-win, really. I've spent $300 on a lot less.
I'll make sure to report back, even though I imagine it will be a month and a half, since they have to get here, plus break in, before I really do some surgical listening.