Weak actuator isnt necessarily a problem, it stil opens and closes as it would if was new . However, when you run high boost levels with a stg2 the extra force put on the wastegate from the high exhaust gasses pushes the wastegate open as the weak actuator can't keep it closed. This results in boost tapering off artificially quickly at higher rpm. Fitting a forge or uprated actuator keeps it closed and more power can be made by the turbo.
