The basic requirements for a properly running engine are fuel, air, compression, and spark. Before increasing your engine's power, it's wise to ensure all maintenance is up-to-date and these processes are performing as intended. A weak spark from your ignition system can result in misfiring, rough idling, poor gas mileage, and damage to your catalytic converter, all of which hinder performance.
Fits: BMW 135i/335i/535i (N54), BMW 335i/335is (N55). Confirm fitment with us before ordering.
