"All Linn" ... is it still a good idea ?

All Linn is an superb idea. For best results, you should also give a large percentage of your income to scientology.

Sarcasm aside, as with many brands there is a certain synergy that is of course a product of shared engineering. But all Linn is by no means necessary to attain a good-sounding system. Allow yourself to listen to the different combinations and decide for yourself if it is to your liking. You ask specifically about the Kairn. Are you going to listen to CDs specifically? If so, consider running the Genki directly into the LK85 (or some other amp) and forego the pre for the present. If you do desire a full-featured solid-state preamp though, the Kairn is no slouch. I use a partial Linn system and am fairly satisfied. My one caveat I suppose is to be more attuned to CD players with 24/196 technology, as the digital landscape is changing rapidly. Let your ears (and your wallet I guess :-) guide you. Cheers!

It was never a good idea.

You'll need lots more power to drive Martin Logans. Heck, even the 5140's don't sound their best until actively biamped. Frankly, I would shop around. I sold all my Linn gear (Kairn, two LK 100s, Karik/Numerik) other than the LP12/Linto and went to Muse digital and vacuum tube pre and amps. Linn stuff is nice, but you can do better for the $$ I am a happier camper now.

I am running the Kolector/LK140/Genki/Ninkas and totally love this setup. I would recommend super-sizing the LK85 to the LK140. I have not listened to the 5140s so I cannot comment on them, but I am very impressed with the Ninkas. If you are considering running the Genki off of the LK85, I would think twice. I don't think it sounds nearly as good as going through a preamp.