G'day,
Is your new model of the M113a1 FSV the AFV Club kit, or does it look like this ?.
If it looks like the photo it's a Vietnam era Aussie modification, fitted with the 'Saladin' turret, if it's the AFV Club, that is also an Aussie modification with the 'Scorpion' turret and a current vehicle. Both have a 76mm gun.
Several companies do track sets for these vehicles, I used the Academy kit and set with my M113 FSV, what is photographed is my own resin conversion set for the Academy kit.
Tamiya re-released their M113a1 FSV, some time back, but it is not accurate to the Australian vehicle.
Rob.