I havn't been to the track yet. I tried indexing the plugs once and there was no difference in performance. I can buy the E3 for $5.45 ea. and the NGK for $3.10 ea. So I'll spend that little extra for the power.
Did you have the data on the cylinder to cylinder EGTs before and after? Are the E3s resistor type plugs? Same heat range? I'm just wondering if there might be something else - a better connection at one or two plugs as a result of the action of unplugging and plugging back in, something like that.
