Don't forget Stug gets spotting scopes with Elephant commander.
People keep saying this, but as soon as the StuG has to turn even a touch, the spotting scope disables and your StuG ends up in a fit of trying to adjust fire to engage with the vision bonus blinking on and off. Always found it was best to have a turreted tank or scout car for getting vision for the StuGs so they can engage freely.