Which plugs are best for performance?

SSVDP said

I think the most important factor is having a large gap ( which means a high energy ignition system). The larger gaps produces a larger flame front to initiate ignition. The details discussed here, copper etc are minor compared to this.
I have only had quality issues with one brand and that was Champion, had a part throttle misfire with new plugs and put in another brand & it was fixed.

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Plug heat range may have been too hot.
I had one instance where the insulator came loose ,luckily the tang/strap held it and it didn't go bouncing in the cylinder.
I'll run any plug that's easily readable, nickel coated. I prefer NGK V power, once heated some they read like any other plug in the correct heat range, so don't buy into that garbage hear say. What's more important is that no matter what brand you use...you select the proper heat range.