for 100USD its a waste of money
product has already been tested in DSM forums and 3000GT /vr4 forums
its said to give minimal improvements in N/A engine but its a huge NO-NO for turbo engiens as it misfires quite frequently
there is also another company selling similar plug , its called Direct Hit.
US forums suggest , its more worthit to fit in HKS Twin Power or MSD or Magnecore although they r much expensive, the pulstar gave too minimum power for USD100