Want message I want to pass is that, don't just say "They're crap" only and ignore some successful stories. I understood, you some may have some bad experience on them. I do believe this and actually, I would like to investigate it, for my own interest, but it seems too far aways from me. If so, why not give the one who ask this question initially a try? Why not telling them one-sided conclusion and ignore the positive results? Even if it proven it's work measured by the equipment, but cannot be felt by the drivers on the difference before and after installing so, do you think it's meaningful and what the buyer want?