i have a turbosmart tee piece, r33 gtr sidemount, and a 3 inch system. Nothing major. I replumbed the controller from the actuator to the intake pipe myself with new vacuum line just to make sure. If i i turn the boost down it doesnt happen as bad. Ill try replacing the piping from the turbo right through.
Have just bought some bcpr6es plugs. gapped to .8 im putting them in this afternoon. should be helpful i hope