Who is it you are refering to that waits till after 6k to feel power. I just dont get it. If your car makes full boost at 4k then dont floor it below 3k. Its that simple. If you are constantly waiting for the mystery in a car that makes full boost in the 4500rpm range then thats your fault. Learn how to drive or go buy a turbo deisel that makes 1000ft/lbs tq at 2k rpms.