Chris,
With the exception of the 340, unless I am incorrect all the other Teres models are upgradable to higher models in the line. I would assume that this would basically not be possible even going from the Teres 265 to the 340. The only parts that seem to be the same between the 340 and the rest of the line appear to be the bearing, the spindle, and the record clamp. Also, with the 340 I presume that a smooth spindle to accept a Sota Reflex clamp would be available, as I had asked in a PM for the other units in the line.
Rich Nelridge