F1 tuning claims 30% hp increase, 40% tq increase, you believe it?

Stock everything exept straight pipe exhaust which probably wont change hp at all lol… Im gonna get the print out from BEFORE the tune and leave it on my front seat so they see what im doing lol… As long as I get a noticable increase however im fine with it, even if its only a 20% increase, thats still alot for the money.