Why manufactures don´t burn in their amps and ...

Rleff- Once you've purchased a hi-end power cord(ie- Synergistic research AC Master Coupler, PS Audio XStream, Zu Mother- or better than those mentioned), and burned it in; you will understand the changes through which it will progress(the electrically biased ones excepted). That depends on the resolution of your system and your ability to discern the differences(system variances and aural acuity/training differences existing in so great a divergence).

Rodman99999- I did purchase a set of kimber power cords don't remember the model but it does not have a network on the cable and will be installing them on pair of audio valve challenger 180 monos I just picked up on Audiogon and am looking forward to hear their performance vs the signal cable cords I had before.
Do you think it is worth putting a high quality ac cord on my soundlab m2's backplate?; Let me hear your point of view.

Rleff- I used to own a pair of Acoustat Model IIIs, and was just recently wondering if I would have heard any difference with some of the PCs I've got now. The voltage that electrostatics use is charging the speaker's diaphragm/membrane, and not providing gain to any kind of signal. That's one of the very few applications in which I believe would be hard to discern an improvement(No experience/just a guess). Then again- I've heard that Martin-Logan CLS's can be improved via upgraded PCs. You could plug those Kimbers into the SoundLABs,(before using them on the monoblocks) as an experiment(I would).

I think that's a great idea I think I will use the signal cables first and then try the kimbers next;thanks

Because they simply tend to 'UNBURN-IN'and that is logical..Next time find out for yourself when you buy a pair of new amps!! Run a varied signal through one of
them for 48 hours-no more needed. Then listen to it in
mono-carefully. Do not rush. Then listen to the unplayed one for comparison-in mono. Now unhook the first one and
place it in another room for 2 weeks. It will not sound
as good as it did before and not as good as the second
one you had been playing for 2 weeks. It is changed=
UN-Burned-in!