Restore dependable spark isolation and secure coil-to-plug contact with the ThunderCore PRO Coil Boot Kit 900-P2101-4. This OE-replacement kit is a direct-fit for the 2004-2006 Subaru Baja, 2004-2010 Subaru Forester, 2005-2009 Subaru Legacy, 2005-2009 Subaru Outback, 2006 Saab 9-2X, and 2006-2014 Subaru Impreza — see the Buyer's Guide tab for engine specifics.
In coil-on-plug (COP) and coil-near-plug (CNP) systems, the boot forms the insulative path between the ignition coil and the spark plug. Heat, vibration, and chemical exposure can degrade boots over time, leading to arc-through, misfires, or hard starting. If worn or cracked boots are the cause, this kit replaces them to help restore proper high-voltage insulation.
- Heat & chemical resistant: built from high-temp silicone and reinforced materials to resist oil, fuel, and under-hood heat.
- OE-replacement quality: engineered to match OE dielectric strength, boot length, and connector geometry.
- Restores insulation: replaces degraded boots to support proper spark isolation and limit voltage loss.
- Complete kit coverage: includes the boots, springs, and insulators needed for full-cylinder service — ideal for ignition tune-ups or preventative maintenance.
Interchange: 184082 · 9007S
