[M5 TT]

But is it not the case the ecu will give up to1.5 bar of boost to achieve 560bhp?

At sea level 1.2 bar of boost is enough for 560. Drive into the mountains where air is thinner 1.2 bar of boost won't be enough or in very hot humid countries again 1.2 bar won't be enough to make 560 so the ecu will give more boost to attain the required amount of torque

Is there an obd reader I can buy that will log boost I will see what mine is doing? I am sure there is just not looked into it yet