The LCD-2 with fazors has a smaller soundstage, but better treble extension and linearity in the mids to treble. Much more detail than the LCD-2C. These also accentuate the 1 KHz peak much more, which to some can be shouty. The cups are made of different woods and sometimes aluminum. These have lambskin leather pads and can come with the older padded headband or the newer headband with comfort strap.
The LCD-2C is a reissue/reimagined version of the original LCD-2 with no fazors. The cups are a crystallized carbon composite material. This results in a wider soundstage, but there is much more uneven treble which results in some interesting peaks. Even though it measures much darker than the Fazor LCD-2, it can sound more exciting at times because of it. These use the protein leather pads and only come with the newer headband with comfort strap.
LCD-X is like the LCD-2 Fazor, but much more detailed in the upper mids and treble. These also use the lambskin leather pads or protein leather pads. The most recent version uses the same cup materials as the LCD-2C. These can come with the older padded headband or the newer headband with comfort strap.
You also may want to try hifishark.com. it’s like the travelocity of audio equipment, you can setup custom searches for items from all over the world. Pretty neat site.
I installed these fazor wave guides in my 2020 LCD2C and the results were staggering. The 2C’s famous “Wall of sound” became slightly smaller but much more defined, with considerably better vocals, treble, and slightly less bloom on the bass but more precise and tighter bass to my ears. The soundstage improved as well, with better centre definition and general instrument placement. These things actually change the sound of the 2C significantly, and I’m glad I got them as now I can listen to them with the guides in or out as my mood dictates. If I want the more well defined sound of the LCD2 I leave them in, and if I want the huge, smooth sound of the LCD2C I take them out. It’s close to the best of both worlds without buying another headphone, whooo hoooo!!!