• Iridium IX spark plugs, box of 4
• Iridium fine wire center electrode, 6x harder than platinum
• Tapered cut ground electrode for improved starting and throttle response
• Designed specifically for the performance enthusiast

Built for the Performance Enthusiast Specifically

NGK Iridium IX spark plugs are specifically designed for the performance enthusiast, providing outstanding acceleration, high fuel efficiency, and durability rather than being a generic all-purpose plug marketed with performance language. Iridium IX plugs offer extreme ignitability and exceptional anti-fouling, two characteristics that matter enormously for an engine that's been modified to run leaner, hotter, or with more aggressive ignition timing than stock. The iridium fine wire center electrode's durability is six times harder than platinum, holding its precise firing characteristics far longer than a standard plug. That's exactly the kind of thoughtful design worth paying for.

A Tapered Ground Electrode That Actually Improves Response

The tapered cut ground electrode design provides genuinely improved starting, idling, and throttle response, a real functional benefit rather than just a different-looking plug. For anyone running a tune, bolt-on modifications, or increased boost, a properly matched performance plug like this one is a small but meaningful part of getting the most out of those upgrades. It's a purpose-built plug for a driver who's actually pushing their engine, not a generic upgrade for a stock car. For a component this critical, that level of engineering is worth having.

Straight From Subispeed

A genuine performance spark plug upgrade for your Subaru — built specifically for an engine that's been modified, not a stock daily driver.