Perhaps I have the time to deconstruct your post because my high IQ has made my doctoral program incredibly easy for me and obviated the need for much study :)?
The reason I responded to your post was because once upon a time I was that child with the high IQ. I grew up in a blue collar area, and my parents decided that to be normal I could not be enrolled in any special programs. I was sent to Catholic school, had 20 kids in my class, and was always incredibly bored. When I was about 15 I was given the Wechsler Adult Intelligence test by my sister, who had to administer a number of IQ tests as part of her requirements to become a school psychologist. I scored a 147, while everyone else she tested was under 120. Her professor was wary of my score, and thought she may have made mistakes when testing me, so he asked that I come in and take some other tests. He gave me a test called Raven's Matrices that had 36 questions on it and I got 34 right, which apparently confirmed my previous score. I reported this shocking turn of events to my parents, and they replied that they already knew I had a high IQ. They had taken me to a psychologist after I read a headline from the newspaper at age 3.
The upshot of this perhaps pointless story is that I would have been much more content as a child if I had been in a more stimulating environment. I had plenty of friends, was good at sports, but still I always felt out of place. It was of my parents' belief, however, that I would turn out weird if my upbringing deviated from that of my older siblings.
A 160 IQ is incredibly high no matter what psychometric is being used. Your son is probably showing these hyperactive symptoms because he is bored. Yes, it is important to learn to function practically, but it can be very alienating for a kid of 160 to be among a group where everyone else is less than 130. I realize this sounds pretentious, but think of it the other way around. If a child with an IQ of 100 was placed in a gifted class of kids all with above 130, he would definitely feel like the odd one out. Remember that Simpsons episode where Bart copies Martin's answers and ends up in the 'gifted school'? If you haven't seen it, suffice it to say it doesn't turn out well. It wasn't until college that I felt understood, and it was like a huge burden was lifted from me. So, while it is important to keep your son grounded, I do think that it would be beneficial to realize that his higher IQ is not just a boon, but something that will bring up other issues and necessitate its own kind of nurturing.