Originally Posted By: PandaBear
If you have some OBD / CAN tool that you can read the individual cylinder's misfire rate, you can check the before and after, that'll be easier than using a scope at a precision controlled load / temperature / throttle.
Most of the great feeling people get are not placebo, but the sharp edges of a new plug over a worn out old plug.
In addition to gap and coil, the firing edge sharpness and electrode diameter also make the difference. Material difference usually only means you can tolerate the stress and make the tip finer.
Good point about the misfire rate. I took a screen shot from my OBD2 tool while the car idling with bosch +4, but it didn't include the misfire rate. I doubt there is any as the plugs have only somewhere 4000-9000 miles. I'm planing to capture similar data after the plug swap to Denso TT. Since I have the data on MAF, RPM, and injection volume, I should be able to see if there is any improvements in fuel efficiency at idle.