You going to ignore KTs armor, penetration, damage against vehicles and the fact its stock?
That's pretty convenient.
ISU:
Target size: 26 Sight: 35 Speed: 4.5 Accel: 1.4 Rotate: 16 Armor: 340/155 Health: 1040
AT Shells:
Range 5 - 70
Penetration near 260
Penetration mid 230
Penetration far 200
Deflection damage 120
HE-Shells:
AOE Radius 6
Distance near 0.25
Distance mid 1.1
Distance far 6
Damage near 240
Damage mid 60
Damage far 36
KT:
Target size: 26 Sight: 35 Speed: 3.8 Accel: 1.4 Rotate: 25 Armor: 375/150 Health: 1280
Range 0 - 45
Penetration near 240
Penetration mid 220
Penetration far 200
AOE Radius 4
Distance near 1
Distance mid 2
Distance far 3
Damage near 240
Damage mid 84
Damage far 12
THIS means:
KT is slower, more expansive, less range, more armor, more hp, less penetration, less AOE, have turret, nondoc unit...but needs huge investments
ISU has more range,more mobile,less hp, equal armor (front) back has more armor, more penetration, more AOE, no turret, is doc