I got my new Mono Extremes (non SE) early this year from Klaus and they were red boards.
From what I can gather from Klaus he worked for quite awhile on getting the blue circuit boards to work as an SE upgrade and made a couple this summer for a few people. He was initially not sure if they would fit or work in the case or the design as they are thicker and different than the reds.
There was a lot of interest in them after the infamous guy from Canada created a big stink when selling his new SE blue board Mono Extremes after only having them a few weeks in July.
Klaus had a bunch of requests for them and began taking orders so he could order the blue boards and other special parts in bulk.
Klaus is considering making this SE version his top of the line model next year and offering it as part of his lineup-not just a custom design.
He states he feels they sound better than the redboard SE, but was not real specific.
I sent mine in for the upgrade two weeks ago. Not sure of ETA-sometime this month.
I did chat with the guy from Canada who had a regular red board SE Mono Extreme pair and the new maxed out SE Blue board version. He said they were like the regular SE's "on steroids" whatever that means.
I trust that Klaus feels they are a worthwhile upgrade from the Mono Extremes.
I have no idea how they would compare to the regular SE Mono Extremes.
He is excited about them and he really is gifted and based upon my experience with the regular Mono Extremes I went for it.
Will let people know. The only deficit I felt the regular Mono Extremes might have had was a bit of a lack of transparency.
I am guessing the SE in any version addresses that.