When tuned, the factory Bosch spark plugs just don't hold up in BMW N54 and N55 engines. Upgrading your spark plugs is a must.
Fix those timing corrections and misfires with a set of NGK 2 step colder sparkplugs.
- (6) NGK 97506 "2 Step Colder" Spark plugs.
*Optional, BMS Spark socket tool.
Compatible with BMW 135i, 135is, 235i, 335i, 435i, 535i utilizing N54 or N55 Engines