Question on FR 66s

P2S:
Mounting Distance is 295mm

Geometry
Well, it will work with whatever you choose or prefer. Most Arms have Problems with Stevenson based on Design flaws, the FR-64s /66s go easy through the most demanding inner tracks.

Cartridges
The energy transfer from that Arm is unique, Cartridges which are designed to move their energy via Headshell into the connected Arm, work very well with that Design. Koetsu also. From my experience, it is THE Arm for Koetsu. Never found a better match with those carts.
Never had a weak result with any - modern - cartridge I used, no reason to worry.
May I suggest to use good cartridge leads for the Headshell you prefer. Most stock leads are inferior, try Oyaide, Orsonic..the performance gain is interesting :-)

Pani,
I think there is no general rule for compliance, effective mass of tonearm and superior sonic result. The formula for that is only a formula but you have different Arm materials (steel, titan, wood, aluminum for example) all have totally different energy transfer abilities, you have Unipivot arms, dynamically balanced Designs and so on...and you have different Arm geometries which are also responsible for superior or inferior tracking ability ...
To make a very long story short, you can all strip down to the abilities of the Designer. You will find endless examples for top sounding combinations which are not a 10 in the 8-12 formula range and you will find mediocre sounding combinations which are a 9.9 in the calculation.

FR-64s
the alternative P2S is 231,5mm

I think that thread was deleted based on aggressive posting from a mexican member which had a lot of personal attacks when I remember right.

04-22-13: Halcro
......and the Fidelity Research arms have a control and authority which is immediately obvious.
The images are stable and pinpoint whilst the soundstage is the widest and deepest you will hear if the vinyl contains this information.
The bass depth and control is quite astonishing.......but the real highlight I find.....is the complete relaxation that one feels when listening.
These arms allow one to forget entirely about the electro-mechanical gymnastics involved in the execution of musical extraction and completely immerse oneself in the music.
You will find it difficult to stop dragging out long forgotten records and re-discovering

A spot on description.
All that is responsible that my records never stop to amaze me when I listen to them via those Arms. Even the most demanding swings go with an "ease" which is unique. And all that is summed up in a "liveness" you can hear in the 1. Minute, like opening a window and breathing fresh air.
The FR-66s is the King of Arms.

... works much better than Graham Phantom 2 supreme 12 inch. I had Graham for about a year and never could dialed it in to my liking with various cartridges that I have and I finally sold it.

The alignment tool (flip) is correct only with the Standard 9" Ar,. Used with the 10" or 12" Arm Wands the cartridge alignment is wrong. And you can hear that normally. But on the other side, on some official demos they run that way and got great reviews from the magazine people.... :-)
Unfortunately Graham forgot to put a notice about that in the Arm boxes ...

but even when done right, the 66s is still a different world (and the Phantom supreme is really good)

However, I was told that Lyra was designed and tuned with copper wire in mind (don't know how true this is though) so I definitely want to try that.

from the signal transfer ability Copper is 100% in its highest, purest availability (Audio Engineering Society) so that is the Standard based on AES
Silver has 106, that means, no other material on our planet can carry more than silver, 6% more than copper, 16% more than gold and I think, more than 45% more than brass...
Some cartridge manufacturers know that and use silver plated pins, some audiophiles know that and use silver headshell leads + plugs, some Arm manufacturers know that also and use silver internal Arm wire, some cable manufacturers know that also and use high quality DIN Plugs ...makes some sense for the ultra low MC Signal....my advice for that is, think about that, check your Cable of choice and also the used RCA connectors (most are inferior, even in combination with very expensive cables) and of course, the quality of the RCA jacks from your Phonostage.... :-)
Normally any Signal is degraded here seriously....MY Pods are $200,-- for example, not the usual $8.95 ...
Good sound is based on knowledge about what is responsible for what ...

I thought you guys had hard-wired your FR tonearms, so to have an uninterrupted run of wire from the headshell plug to the phono stage

I use them stock and I also know nobody who modified them to run them direct.
Well, in a way it is the same idea we find in Graham Arm discussions, more pins, more contacts, more resistance to direct wired Arms. But the Graham Arm is still much better than all other current designs (some won't agree but there is a difference between "I like something" or "better"), so the secret of superior sound is somewhere else. But where?
A straight piece of Arm wood with Valhalla cable and 2 RCA plugs does not help much in comparison with other Arms.
So I think, other Design ideas have MUCH more influence to superior sound. The 64s for example has some very interesting internal solutions and when someone would build it again with identical specs and materials, it would be easily above $14k.
The 64s was a very expensive Arm when it became available. I think, it was among the top 5% from pricing.
The 66s was a different Galaxy, super expensive, very, very rare. 64s was from production numbers probably factor 10 or more.

Well, distortions can be also those which are created in the area above the eyes. When brain is clipping.

At the Munich High End Show is a Manufacturer with a new calculated Alignment System (some here know it) and what amazed me totally was the amount of visitors, dealers and Importers who showed a very huge interest in that. Whenever I was in the area of that their arguments were ALWAYS the same: way too much nonsense out there (I agree with that btw.). I also saw wrong alignments, Arms with a Geometry which made me wonder....and the discussions among audiophiles what .... everyone is a specialist with deep knowledge :-)

Dear Raul, don't worry, no one was interested in a product made in Mexico (a small joke was created but all were happy when it was corrected). I am not ignorant but I am afraid that I forgot more than you will ever learn. Well, I know that you will never get it, but I am not in marketing, nor in photography nor in dealing with something :-)
Too bad for you
Regards and enjoy the music
S.