Q#1: Defer to Shiv
Q#2: The switch allows you to change what map you want to use(think e60 M5)
Q#3: The dyno shown above is with exede AND exhaust. I don't think he has had a chance to test the exhaust by itself.
Q#4: He doesn't go to the track, he will have numbers as soon as one of his customers reports back to him.