drive it with the 91 setup for at least a month. give the computer the full time to learn everything and give yourself full time to get used to how the truck behaves. then go back to the stock tune and tell me there's no difference
back in the summer, i had mine with the 91 tune for two months - had to go back to the stock for two days while i had some work being done. it was miserable to drive, i couldn't wait to get the 91 tune back.