One of the main components of the ignition system in your BMW 335i is the spark plugs. The spark plugs are powered by the battery, and occasionally will need to be changed simply due to wear. This is part of the general maintenance that needs to take place with your vehicle to keep it running smoothly. When replacing spark plugs for 2007-2010 BMW 335i, Bosch is the ideal source for parts that will be dependable and long lasting. Once you have replaced the spark plugs, the vehicle will start without a problem and run like new!