In a conversation with me on Friday, Klaus mentioned it just doesn't work in his current house (too big for Sheri's taste) and he might sell it.
He thought he would want about $7K. This amp originally was $36K
It is big, I think around 375 LB's

Almost all of it is power supply and heat sink.
I currently have my mono 400's driving my VMPS RM40's extremely well...no need to bi-amp as far as I'm concerned

Not sure why, but the stereo 400 was $2K more originally than the mono's
Anyway if you have tough to drive speakers like the RM40's and want an amp that can do it with ease, you might want to contact Klaus.
There are less than 50 of these in the world and were made around the mid to late 90's....I wouldn't hold my breath for any to come up on Agon.
The first more than 100 watts is class A than it goes to class B.
It is stable into less than .5 Ohm loads.
Highly recommended if you want a clean picture on the music with little to no coloration and dynamics out the wazoo.
Pics of one of my mono's are in my gallery.