It seems likely that the upgraded tank will be very similar to the TAM 2C upgrade prototype co-developed by the Argentinan army and a number of Israeli companies.
It is understood that the armor protection, the main gun and the powerpack remained unchanged.
The Commander Open Architecture Panoramic Sight (COAPS) from Elbit serves as commander's sight, it is likely that the gunner's sight is also supplied by Elbit.
"Argentina has agreed to a USD111 million contract with Israel to upgrade 74 TAM main battle tanks.
The deal was signed by Argentine minister of defence Agustin Rossi and Mishel Ben-Baruch, director of the Israeli Ministry of Defence's International Defence Cooperation Division (SIBAT), on 26 June.
Rossi announced that the contract includes an offset agreement clause that will establish joint ventures to oversee technology transfers to Argentina. The work is to be performed at the 601 Arsenal Battalion in Boulogne Sur Mer in Buenos Aires province.
The contract covers 74 TAM upgrades and is part of the Argentine Medium Tank Modernisation Programme that began in 2009."
Source: Jane's IHS, The Times of Israel
Author's opinion: I think Argentina has bigger problems than the TAM. Upgrading a total of 74 (!) tanks for more than one million USD per piece seems a huge waste of money, considering the location of Argentina - Chile bought used Leopard 2A4 tanks for less money (!), which are much better .