Well - I think its nice to be able to compare equipment without having actually purchase it and use it...
But that's exactly my point - you simply cannot compare equipment based on specs, THD or any other. Knowing the THD spec for the UA5, modified or otherwise, will not tell you how it
sounds. The only way to find out how it sounds is to
listen.
There are plenty of people using the UA5, and a few of us have even put together some comparisons of the UA5 v. other gear. Download or post an ISO for some recordings using the mics + UA5 flavor you want to hear - I bet someone here runs it or has some recordings and it will give you some idea of how it sounds. Though obviously not as good an idea as a head-to-head comparison with a set of gear you know well. But it'll tell you a heckuva lot more about how it sounds than the specs do.