The purchase of a zet transrotor deck is an important investment and it is rare to be able to buy a zet 1 or zet 3 with all the options you want.

Depending on the zet model you buy, there are several options available.
The zet transrotor is often sold with a mm uccelo or merlo cell and a rega rb 330 or 880 arm and also the Jelco TRS 800 arm for older models.
If you have a Zet with a mm uccelo cartridge, the first option is to switch to a MC merlo or merlo reference cartridge. This evolution is audible from the first notes. If your phono amp doesn't allow you to use low level cells (MC), I advise you to use the Hana brand which offers MC cells - Diamant Shibata Nude version SH which have the particularity to be used on a MM amp.

If you already own a Merlo MC cell or another brand, the most interesting option in my opinion is the purchase of a TMD Kit. This easy to install kit significantly improves the airiness and subtlety of the sound, a real plus.  

The arm is also a very important part of the turntable. Since 2021, Transrotor has been offering the new Rega RB range and its models: 220, 330, 880 and 3000. They integrate the ground directly into the cable and do not have a cell holder. The RB 880 model uses the latest Rega tube which, thanks to its new design, has the particularity of reducing mechanical stresses and resonances, thus increasing its rigidity.
If you prefer a Jelco TR800 type S-arm, I suggest the Japanese brand Sorane and its superb TA 1 arm. If its design is classic, the conception is not: machined aluminium, high quality bearings, the rear counterweight can be exchanged and the bayonet cell holder can be removed at any time
 
If you are happy with your turntable's equipment and want to optimise it, look at the phono part of your system. If you have an MC (low level) cartridge, a phono stage with extended settings will increase the adjustment possibilities of your cartridge. Some models like Lehmann Audio and its black cube or Aurorasound with the prima or more recently the Vida allow you to exploit your cell to the full and take it very far. Here is a first approach of the possibilities of optimization of your transrotor, do not hesitate to contact us if you wish to further refine the possibilities.