Iridium Spark Plug Set [Mk3 / Mk4 Focus ST] Fit at HQ:Yes Holster with t-slot mounting

Holster with t-slot mounting

HQ fitting time: 3 hrs

Unlike other upgrades that deliver just peak or high RPM power

this noise becomes exacerbated so cars that seemingly didn't whistle

Please note: Supplied in a pack of 4 plugs

Iridium Spark Plug Set [Mk3 / Mk4 Focus ST] Fit at HQ:Yes Holster with t-slot mountingEcoBoost engines running substantially higher boost pressure or increased levels of tuning compared to the OE power output can experience reduced spark plug life, resulting in lower engine performance, misfires and rough idle. Increased wear is typically seen in the form of increased spark plug gap and degradation of the electrode. Using spark plugs that are optimised for increased power ensures maximum performance. Extensive in market validation at