Thorens TD 166 MkII with SME tone arm

I'm planning on upgrading my TD 166 Mk II with an SME 309, IV or V tone arm. Has any one done this? any advise? I haven't bought the tone arm yet.
Faraday Blue, if you aren't pulling my leg, I have to tell you the bad news that the 166 is not one of Thorens' finest, and not worth a high-end tonearm, or to put it more accurately, an expensive tonearm. Thorens models which could be considered of great quality include the TD160, TD125, TD124 'tables. The TD166 has a plastic inner platter, a no-no. If you want to keep it and upgrade it, then go no further than an RB250 (which would still outclass the 'table, however), as this cost would be minimal. For the price of a higher SME you could buy a whole new high-end 'table, and then put an RB250/300 on it, and have change left over. Suggestions for good 'tables abound on this website, but beware and trust your ears: never buy sound unheard.
Thanks for your response. I've owned this table for over a dozen years. I've done modest upgrades over the years to make it sound better, i.e. plumbers putty inside the plinth, a cardas golden cross phono cable and a benz micro silver cartridge. I was under the impression it was worth upgrading.
Faradayblue, I'm not saying it's not worth upgrading, I'm saying it's not worth the expense of current SMEs. A Rega RB250 will give you a great leap in performance over the Thorens arm for a fraction of the price of those SMEs you listed, with an arguably equivalent sound quality. I buy old classics all the time and tweak them to their best performance, but there is a limit beyond which it is no longer economically feasible. If you have the cash, and aren't attached to your 'table emotionally, then for the price of the arms you listed you could get quite a serious rig, or even one of the new Thorenses which come with Rega arms included, the 850 particularly getting good reviews, a true high-end 'table, and selling new for $900 including Rega arm, though you wouldn't recognize it as a Thorens. I'm not sure if you're aware, but the cheapest SME you list sells for $1550. Since you have lived with the Thorens for so long, then it is not an issue of money, but of enjoyment and quality. The Rega arms will stand up in the company of the SMEs without embarrassment sonically and give you more than you expect. If you need some good info on Thorens 'tables, the best website I've found so far is at, which has a section towards the end on various Thorens 'tables and their build quality/value. Good Luck.
Listen to Johnnantais, voice of experience and wisdom.
The overwhelming opinion among Thorens experts in Germany is that the Rega 250 is not a significant improvement over the often underrated stock TP16MkII arm, especially since a Rega costs twice the used price of the Thorens.
Thankyou for all the opinions and advise. You've changed my mind regarding the arm I'll put on the TD166 MkII. There seems to be more Rega 250s and 300s available than TP16MkIIs unless the TP16MkII is attached to a TD160. If the cost of a TD160 with tonearm is cheaper than the Rega 250 I may go that way. Then I'll have another table that I can upgrade at my leasure.

Regarding other tweaks: Can I do better than the Benz Micro Silver with this combination? Should I change the mat? Suggestions appreciated!
Faradayblue, Yes, change the mat! You can then transfer it to a TD160 when you get there. I would wait until you get a better arm before upgrading the cartridge: you will hear a significant improvement with the arm alone, and the mat. There are fans of all kinds of mats on this website: for myself, I am considering the Boston Audio Design Mat1, a heavy graphite mat which will push the performance of your 'table by a surprising amount: I'll be putting mine on a Lenco and on an Ariston. There are so many mats I've forgotten all the names: start a new thread to the effect of which mats work best with metal platters to get this info. I have kept the bearing/platter from a TD160, which is a work of art, one of the best I've seen. I plan to build a whole new 'table around this platform. With the 160 you'll have the platform you're seeking for those SME tonearms, and don't believe anyone who says these 'tables aren't "serious."
Again the stock arm properly cared for and setup is quite good on the TD 166mk2 mine sounds excellent with a Grado black a real cheapo..but will accept many finer cartriges to say the least..great arm "bad advice" sometimes...
This is nonesense the Toanarm on the stock TD 166mk2 is excellent IF you take care in cartridge matching and the arm is in good shape to start with..Thornes new how to make arms..this is a your money
SME 309, V and IV cannot be mounted on old sprung Thorens, or even LP12. The arm is too heavy for the designed load of the tables. Stick to light arms like the current SME M series or the older 3009 series.