Ignition Coil + Spark Plugs for Subaru WRX STI (2005-2007) 2.5L

Direct-Fit Ignition Coil and Spark Plug Kit for 2005-2007 Subaru WRX STI (GD)

What it Does: The ignition coil and spark plug kit replaces aged factory coil packs and worn plugs on the 2005-2007 WRX STI to eliminate high-boost spark blowout, restore combustion efficiency, and sharpen throttle response.

The Stock Subaru WRX STI Ignition Thermal Breakdown

The horizontal cylinder arrangement of the EJ257 boxer engine places the ignition coil-on-plug boots in direct proximity to hot cylinder heads and exhaust manifold heat. Over sustained thermal cycling, the internal primary and secondary copper windings within the stock coils suffer dielectric fatigue, leading to secondary voltage decay and micro-arcing. Compounded by widened gaps on eroded spark plugs, the degraded ignition system struggles to ionize dense air-fuel mixtures under manifold boost pressure, manifesting as erratic idle, hesitation, and boost-dependent misfires.

The Engineering Solution

This comprehensive tune-up kit restores high-energy ignition timing to factory operational tolerances. Featuring heavy-duty dielectric epoxy encapsulation and heat-resistant silicone boots, these direct-replacement coils prevent arc-through and resist high-temperature degradation within cramped GD chassis engine bays. Paired with fine-wire Denso Iridium spark plugs, the kit lowers ignition voltage requirements while producing a concentrated spark kernel, ensuring reliable flame-front propagation and complete cylinder burn across the entire rev range.

What's Included

• 4 Ignition Coils replacement for UF508
• 4 Denso Iridium Spark Plugs

Technical Specifications

Compatibility

• 2005 Subaru WRX STI 2.5L turbo
• 2006-2007 Subaru WRX STI 2.5L turbo
• 2007 Subaru WRX STI Limited 2.5L turbo

Frequently Asked Questions & Fitment Warnings

Does this fit the GD WRX STI?

Yes, this is a direct fit for the 2005-2007 Subaru WRX STI equipped with the EJ257 engine. This kit is not compatible with 2.0L EJ205 WRX engines or naturally aspirated EJ platforms due to differing coil dwell profiles and harness connector configurations.

Are spark plug wires required for installation?

No, the EJ257 utilizes a direct coil-on-plug layout, meaning separate plug wires are not used or included with this kit.

The Subaru Performance Caliber

Engineered to handle intense boost pressure and rapid throttle transitions, this direct-fit ignition kit ensures your turbocharged boxer engine delivers uninterrupted power delivery, razor-sharp response, and clean combustion pull after pull.