1) Do drones take Stun damage?
Only if it's electrical, in which case it's treated as Physical. So no.
Electronic equipment and drones can also be affected by Electricity damage. They never suffer Stun damage so Electricity damage is Physical when used against electronics and drones. They resist damage as usual and suffer a secondary effect if they take even a single box of damage.
The secondary effect for electronics and drones damaged by Electricity damage is shorting out or overloading. In game terms this is reflcted as secondary Matrix damage equal to half the Physical damage rounded down.
2) Do drones take no damage if the DV doesn't exceed the armor?
I hadn't noticed that the paragraph for drones doesn't specify that they follow the same rule as for vehicles.
As I see it, there are two ways of reading those paragraphs.
1. Inclusive; the rules for vehicles in the first paragraph also apply to drones, except where condition monitor is concerned (6+(Body/2) instead of 12+(Body/2)).
2. Exclusive; the rules for vehicles in the first paragraph do not apply to drones, so they take the full DV of an attack even if it doesn't exceed armor.
Personally, I believe the former is correct, but I've got no book proof for this.
3) Does this mean that tasers are actually pretty effective at damaging cars?
Did you mean "effective at damaging drones"? If yes, then yes, tasers work well on drones if they are in range. If you mean to say cars, then no, I wouldn't say the are "pretty effective" at that, because cars still only take the base damage + net hits. Tasers are going to be more effective in terms of DV than light and heavy pistols, as well as light automatics, but the range on a taser is incredibly short comparatively. So it becomes a value call if they are more effective depending on what you compare them to.
