To BigFlamer. Your wife's friend is partially right. Boxers are hyper but they get it out of their system pretty quickly and will then be content to just be near you after you give them proper attention. 30 minutes of exercise 2X daily is plenty.
Do note they can vary in size considerably. This is a picture of my 3rd boxer at 13 months. He is now almost 2 and closing in on 90 lbs, with ribs showing. Boxers are the bodybuilders of the dog world: very strong and muscular. On average Boxers weigh around 60-70 lbs so proper training is a must.
As far as cropping the tails, I believe there were originally two reasons: 1) they're prone to breaking and 2) they're prone to cancer
Ear cropping: 1) better for the dog, in the event it does get into a fight, there's less leverage for the other dog and 2) less maintenance for humans, fewer ear infections due to trapped moisture, etc.
These days I think it really boils down to personal preference as you can show the Boxer with cropped or uncropped ears. This is probably more information than you wanted to know about Boxers but I couldn't help myself. Atomic, your puppy is cute too, even if it isn't a Boxer.