How can I solve a Linn

I got a great deal on an all-Linn system that includes a Genki cd player, Tukans biamped with a Linn Majik and a Linn LK85, and Linn analogue interconnects. It sounds great for the money, but it's a bit light on the bass and, worse, on some music very bright to the point of fatiguing (solo accoustic guitar/vocal stuff, for example). Can anyone suggest how I can adjust the bright, almost harsh, sound? Different interconnects? Expensive rack/isolation? Room adjustments (e.g. rugs on the walls)? Forget biamping and go back to just the Majik? Go Aktiv or add a sub? Ditch the Tukans? I'm at something of a loss. I fooled around with a couple of different interconnects but couldn't really tell the difference (don't know how people do).

Based on my experiences, having previously owned nearly everything you mention, I'd recommend trying the following:
First, address the room issues if the room is "live." Then, in all honesty, I'd consider ditching the Tukans (and maybe even the LK85 as well if finances dictate) for a pair of Meadowlark Kestrels (hot rod if possible). Do try to audition these first before purchase, preferably in-home. They have a rather good bass response, so you needn't complicate things more with a sub. Go ahead and use the Linn speaker cables and ICs for now, but something like the Tara Prism series might be a good choice at this level. Tara actually mates well with Linn, and will help take any remaining "edge" off. I'd refrain from becoming more deeply embroiled in the Linn "upgrade" path, i.e., "aktiv" etc. Perhaps Linn's weakest link of all is their speakers. Also, don't forget that you can try different permutations of the current system. You can use the Magik as a preamp with the LK-85, or you can run the Genki using the variable outs directly to the LK-85 (something I did for awhile). I think you can make your system much more listenable without taking a bath. Hang in there! -John, aka "musicdoc," formerly "musikdok" P.S. Contact me directly if you want as I've got a lot more free time on my hands lately.
Have you tried moving them closer to the wall? I've found Tukans to be a little bright too. I'm currently using my Majik as a pre to two LK85s. I listened to it with just one of them for a little while to guage the effect of biamping- mostly more articulate bass. Have you has a chance to audition Katans? or Keosas? Your component rack may be playing into it as well. I have decided against aktiv for the time being because the mids and life get sucked out for my system; it appears that the light shelves of my SoundOrg stand may be the culprit after trying all other avenues. My experience with Tara products are that they are very accurate, but I felt they lacked life. The hot rods I heard were with NAIM gear and were nice, but I think you may loose some of the synergy of all LINN components. The last iteration of the Tukan had smoother tweeters, same as the 5140- do yo know how old they are? If bass is because of room size, definitely go for floor standers or gutsier bookshelves. My Paradigm Sutdio Monitors had much more bass than Tukans, so I kept them until I could get Ninkas. Otherwise, it's a REL or a Sizmik.
I agree with Musicdoc. Start with room treatment. Your system will benefit from it no matter what components you decide to use. I too recently had this problem as my speakers are a little bright. I built two bass traps and three wall panels (two at first relflection points and one on the rear wall) and the problem is 90% solved. Good luck. Fatigue is the most annoying problem.