The Linn "Sondek" LP12 is unique both for its effect on the fidelity of analogue replay, and the fact that its manufacturer offers owners of older examples the opportunity to fully benefit from ongoing development. Almost any LP12 can be brought to current specification, or to any increment between.
When recommending upgrades for a customer's LP12, I consider various factors, including the condition/version of existing parts, and the way in which the turntable is used in the home. For example, the customer who mainly listens from the next room while dining, or working, etc, is unlikely to benefit from thousands worth of upgrades. Meanwhile, the customer who often sits down in front of the speakers, concert style, will have a very different experience with Linn's range of upgrades.
This is the primary caveat. Internet anecdotes about these products can be misleading; Linn's own efforts are for naught if the installer is in a hurry, and/or lacks detailed product knowledge - a passion for the LP12 is not, by itself, enough.
When it only makes your records sound different, rather than better. Meanwhile, Linn's factory issued upgrades, when installed and adjusted correctly, do as claimed - and at Promusica we provide a 'prove it' demonstration prior to purchase - so you can be assured that the proposed purchase represents true value, for you.
I suppose I should not risk deterring the reader from buying one of these items, but the truth is: the LP12 that is without SE components, but is otherwise fully optimised and properly adjusted and set up, can impart more musical insight and pleasure than more expensive players from other makers. In other words, you do not need to go to the SE extreme in order to be thrilled anew by your records.