Question about boxer dogs?

I have a boxer, they tend to be stubborn & need someone who is firm with them & will invest the time in training them to be obedient. 'Reward based training' is better with them; they seem to be sensitive to the more physical or aggressive tactics. They are stubborn because they are fairly intelligent & know when they can get away with stuff. They will be sneaky about doing stuff they aren't supposed to do, & if not properly exercised, they can get destructive out of boredom. Boxers don't like being left alone, & bond well with their owners. They can run with you but don't tolerate extreme weather (real hot or real cold) & tend to overheat easily because of their short muzzles, so make sure to bring water with you on your runs. They seem to have short attention spans & act like big puppies. They are pretty active & need a daily walk at least, along with something to occupy their minds. A lot of people do agility training with their boxers. They are clified as a 'working dog', their history includes bull baiting, guard dog, police work, isting hunters in holding down large prey (they do have a pretty strong jaw, don't know why someone would say they have a weak bite?) & they even did circus performing. Boxers are really good (tolerant) of kids & protective of their families. They are prone to health conditions like cancer, allergies & heart issues in their later years. They aren't full grown until approximately 2 years old. Overall, they are an excellent dog if properly trained, require very minimum grooming, & are not aggressive.