Shahed, I have heard most of these systems and would say the First Sound with KWA150SE will deliver that sweet tube tone while being very clear, but it is an expensive setup ($12k for the pre). the Golden Tubes amps when rebuilt are a find, they will also get you there.
all the other gear mentioned in this thread is also top notch, each has a slightly different sound.
another point is that the KWA100 does have a bit of that SS sound where the KWA150SE sounds more like a very clear tube amp. the two models really are different animals and I agree with the comment that the LS100 is already a very tube sounding pre, so possibly upgrading to the KWA150SE and rolling tubes in the LS100 may get you there?
glad you are happy with the speaker!