If you're running high boost, these are the plugs to have. They don't have an internal resistor so 100% of the spark energy goes into the arc. We've seen these solve high-boost misfire problems on 400 hp cars. You'll be able to run a bigger gap, which means a bigger spark and more power. It's the cheapest ignition upgrade you can get.
What's the downside? In theory, more ignition noise in your stereo. We haven't actually experienced that nor have we received any reports of problems from our customers. But you have been warned. You might also get a little burble at idle. These are a heat range 7 which is great for high power, but are going to be more prone to fouling if the car has starting problems. We used to run #7 plugs in all our turbo cars until a few years ago.
For 1990-05 Miatas. Works well in conjunction with our Big Spark kit. Not compatible with the old Link ECU. Sold in sets of four - that's enough for one full car.