@thekong , Very few of us get to utilize equipment in our systems at length if at all before we purchase it and awareness of technicalities is helpful in making decisions as to what you buy or not.
Kuzma makes some excellent equipment. He also makes some not so excellent equipment. Few of us can score a hit every time.
The basic design of the Safir is excellent like the 4 Points. Its effective mass limits it to a small number of very low compliance cartridges. Mr Kuzma's assertion that you can run cartridges with a resonance at 3 Hz would be true in a perfect world but, it is not. Records are not perfectly flat and turntables are not perfectly quiet. There is plenty of very low frequency noise that would energize a resonance that low. I have done this experiment. For yuks you should try it. You won't break anything. Just be ready to use the lift.
@ dover, there are many people who are very capable of analyzing the design of a turntable without having built a single one. By your own argument you are obviously not one of them. Instead of attacking me personally why don't you just explain why I am wrong. Usually, when you see attacks like this it is because the individual is incapable of having a discussion about the technicalities of an issue. Your analogy of the car door totally fails. The door is not suspended by a spring. Although it has detents to hold it open at certain points it will not spring shut when you open it and let it go (unless you are parked on a hill). By having the counter weight on a spring you just add another resonance frequency. The counter weight moves at the same speed and distance as the stylus it's mass is part of the system and can not be divorced.
Turntables (unless you are Nakamichi or B+O) are extremely simple devices. There are many people who have built their own turntable. Precision bearings are readily available as are great motors and control systems. Only and audiophile can make such a simple device as complicated as a General Electric GE90.