@pcosta I think with your question we must distinguish the differences between "restorers" and one who modifies to potentially make better. Do all those fall into the same category?
Woodsong appears to offer plinths and I don't know if he does anything to the 301 like new platter and bearing. We know Artisan Fidelity mods the 301 to a highly expensive level, then we have to ask is it still a 301?
You make a very important point which is completely lost in most discussions. I dont believe anyone offers an optimum reincarnation of the Garrard 301's.
For example in my rebuild I have revisited fundamentals under the chassis that none of the premium rebuilders offer -
1. I have punched out and replaced all the rivets/washers connecting the control levers under the chassis with nylon bushes and telon washers to eliminate noise from metal to metal contact and rattly levers. None of the rebuilders do this. In fact you would think with 3D printing it is now possible to remove all the metal under the chassis.
2. I have decoupled the power switching from the on/off lever so that when you change a record, the idler disengages but the motor continues running. Given that the motors take a while to stabilise it seems crazy to me that no one else has thought about this simple mod. It also eliminates having a 110/230 volts switch and wiring under your low output moving coil. None of the rebuilders do this.
These are just 2 examples. There are a myriad of other possible mods under the chassis that rebuilders have never thought of.
For me the rebuilders change the chassis/bearing/platter and build a plinth, but they faithfully replicate the motor/control systems of yore along with their inherit faults.
And then there are the thoughtless mods - like the aftermarket bearing "upgrades". Most people denigrate the original flat bottom spindle and thrust pad. However changing that profile to a ball and thrustpad actually destabilises the platter and spindle. Think about it - is it easier to stand on a flat surface or balance on a ball. The ball produces hifi but affects bottom end coherency compared to the original design.
I could go on and on. There are more tinkerers out there than engineers.