I have been working on and fine tuning Linn, Rega and other turntables for over 40 years. The LP12 is still the finest record spinner I have heard and is certainly worth upgrading. However, I am having some problems with the figures you mention and the upgrades mentioned. First off an Akito 3 is $2400 and comes with a really excellent cable and a Krystal is $1900 so we are far short of $6000 parts. Secondly I can't see where there would be $1000 in labor. Linn products like tonearms, cartridges, power supplies, etc. include installation in their prices. I do a complete 3 hour setup and fine tune of an LP12 for $225. Unless the original turntable has been highly modified in a bad way I can't see it taking more than four or five hours - I could build a whole new LP12 from its individual parts in less time than that. Then as to the recommended upgrades I feel that the Akito 3 is really only a sideways move from the Ittok LVII. So unless your Ittok is actually broken I would just keep it, buy an Akito arm cable for $400 and put the Krystal on it. There are, of course, other upgrades that are very worth doing but that would require more discussion to see what you are wanting to do.
In the end, I would put a properly configured $7000 (or $12,000 or $26,000) LP12 up against any other turntable at the same price or even higher. The LP12 is an exceedingly musical turntable and I have had a number of customers buy one after comparisons with similarly priced or more expensive turntables. But you do want to do the upgrades sensibly and from the little information you have given on the proposed upgrades I don't think they fit that description. I hope this helps. ThomasOK.
In the end, I would put a properly configured $7000 (or $12,000 or $26,000) LP12 up against any other turntable at the same price or even higher. The LP12 is an exceedingly musical turntable and I have had a number of customers buy one after comparisons with similarly priced or more expensive turntables. But you do want to do the upgrades sensibly and from the little information you have given on the proposed upgrades I don't think they fit that description. I hope this helps. ThomasOK.