that's 100% inaccurate!!
I am not new to the mazdaspeed.. I have had mine since 06.. it has 60K miles on it.. the factory tune is pig rich to help the crap toothpick rods.. mazda slapped this motor together without enough R&D to compete with dodge and Mitsubishi. you can run increased boost on stock tune with upgraded internals yes.. but forged internals in no way corrects the crappy stock fuel trim.. to really run this car safely with a decent amount of boost.. 12-15 psi.. you need some sort of air fuel management... along with the forged internals. some people are running over 10 psi on stock internals.. however.. and ive said this many times. that car is a ticking bomb if they continue.. since the factory wastegate actuator can fail so easily and cause a boost spike.