tonearm upgrade, how far up the food chain?

Regarding the Rega 300 I agree with Stanwal and disagree,
logicaly, with Raul (sorry Raul). I.e. the 'so-so' qualification applys for the original wiring but the Rega is easy to rewire. I bought this tonearm for my son and deed riwiring myself. BTW my son is also reading this forum
so such 'so-so' qualification my 'disturb' our relation.
Regards,

Dear Doug, Your argumentation looks very 'sound' but presupposes much knowlege about,say, analog 'experience'.
I,for example, know that Van den Hul 'swears' by Technics
EPA-100. I would never dream to pretend to know beter. But I bought the Triplanar VII wich is ,say, 4 x more expensive because I regard this tonearm as the most beautiful ever made. But your 'cost-ratio'argument
have some other support. One Dutch firm bought an very expensive 'machine' ($ 20 million) but this machine 'refused' to work. So they asked for an specilist
who give an rap to the macine in 'some place' and the machine was working. But he made expenses claim for $ 4000.
To the questin:'$ 4000 for an rap?' his answer was:'the
rap is $50 but the knowlege where to apply the rap is the
rest'.
Regards,

Thanks so much for the thoughtful comments. I am largely persuaded that upgrading the arm should be a priority, and probably the phono stage, too (which I suspected.) Unfortunately, the Thorens is not the best platform to "build on", as it is limited in the arms it will accommodate, only Rega-type or SME (with a different arm mounting plate, which takes almost 6 months and $200 to get from Thorens.) fwiw, the low output Grado Ref was described as a "budget" cartridge by a knowledgable distributor, and it exhibits slight sibilance in my system; it is good to know it is probably not the most limiting factor in this setup.

Dear Llydc: +++++ " the low output Grado Ref was described as a "budget" cartridge by a knowledgable distributor " +++++

that does not surprise me coming for a " knowledgable distributor " that for that statement and with al respect he is more on the unknowledge side than in the other one.

Maybe a 1.5K cartridge could be name it a " budget " one because that price against cartridges in the 5K price range ( and I can understand this. ) but as Doug point out:
+++++ " Aiming for some cost ratio is largely pointless, since the performance and compatibility of components cannot be judged just from their cost " +++++

Yes, I agree with you: your cartridge is not the most limiting factor in your today set up.

Regards and enjoy the music,
Raul.