I don't think she caused too much damage (or any in this case). What she has done is same as taking your car to the track straight from the dealer and driving at 6-7K rpm for 15-20 mins. Many people track their car as early as 100-200 miles. Is it recommended? NO. Do they still do it? Yes. Does the car drives fine in the long run? usually. The plastic burning smell is normal. I still get that in my car and it's been 1150 miles already.
You are more than welcome to get the car checked at your dealer but if everything is running fine, I wouldn't bother. Seems like you wife did an "express break in" on your new Z...haha
Enjoy!