get the gun, then hull and then turret

the hull is special as it is one of the few MBT hulls with blowout ammo meaning that if you use a turret with blowout ammo you cannot be killed by ammunition detonation (unless you don’t put the fire out), it also has decent armour protection against Kinetic ammunition (AP/APHE/APDS/APFSDS and a few ATGMS) and very good frontal and side protection against Chemical ammunition (HE/HESH/HEAT/ATGMs)

the turret has very thick armour in some places but its main selling point is it has the “ready rack” trait on one of its ammo racks meaning that any shells being loaded from that rack will have an increased reload speed and your tank will passively move ammo from other ammo racks into that rack.

the gun is a further improvement to the 105mm M68 with more pen, a faster reload and better shell velocity with the only downside being less damage and pen compared to the more common 120/125mm cannons which you have to craft from blueprints.