I agree with Miami. Its just a software tweak. When you're dealing with a turbo'd car a simple addition of 1-2 psi can get you that additional 15-20 HP.
And I am glad too see that smash has came to a realization of the true HP increase of the N55 BMS tune.
2012 535i M-Sport
Previous BMW's: 87' 528e / 04' 325i / 07' 335i / 08' 335i / 08' 535i