Spark Plugs — Price Comparison

Spark Plugs for 2017 Subaru Legacy

Spark plugs on a 2017 Subaru Legacy are a wear item with a precise replacement interval, and using the right electrode material matters more than brand. Iridium and platinum plugs hold their gap for 60–100k miles; copper plugs spark marginally better but need replacement three times as often.

We compared 5 offers across major retailers for the 6th Gen platform (2015–2019 6th Gen). Prices range from $9.99 to $35.99 as of the last update.

Best picks

• Best overall: The iridium plug matching your engine's factory specification — same heat range, same gap, longest service life.
• Best budget: Copper-core plugs if you don't mind 20–30k mile intervals — they're cheap enough to replace often and conduct slightly better.

What to look for

• Never downgrade from factory iridium to copper on engines specced for long-life plugs.
• Buy the full cylinder count from one production lot — mixing plug states causes uneven running.
• Coil-on-plug engines: inspect the coil boots while you're in there; they're the usual failure companion.

Sedan note: parts for high-volume sedans are commodity-priced, which works in your favor — the brand-name option frequently costs within a few dollars of the budget pick. Buy on warranty and reviews rather than price alone.

Fitment note

Verified for 2017 Subaru Legacy (6th Gen). Fits 2015–2019 6th Gen generation unless trim-specific exclusions apply. Confirm trim and option codes before ordering.

Prices are affiliate-linked estimates. Confirm current pricing at the merchant before purchase.