stock turbo and actuator limit I believe is where im roughly at which is 330rkw. All I have is 4 inch intake, 3.5 x force system, pwstage 2 intercooler,60lb injectors and surge tank for insurance. The actuator is quite good. Im about to fit a bigger turbo to replace the smaller FG and my tuner (Blueboost)says he might use the same actuator. So the car will be hopefully pushing 380rwkw with stock actuator. Will keep you posted on how it goes. And with the valve springs im only just now doing them with the turbo now for insurance. So they still good for a bit. Hope this helps..