Hi guys. Fitted stage 3 bits to my 4x4 saph and wound the boost up to required settings via actuator rod, once I got past 20 psi my turbo developed a screeching sound on full throttle/boost. It never did this before on stage one 16psi. There's no play in the shaft and no oil leaking out. Appreciate anyone's suggestions. My thoughts are the turbos poss shagged lol! Thanks, Gary.