Ignition component maintenance (spark plugs, ignition wires, ignition coil packs, distributors, etc) is invaluable. When your ignition operation suffers so does fuel economy, engine performance and overall wear on the engine. It might have even gotten to the point where your Check Engine Light is flashing at you. That means the vehicle is misfiring and you should stop driving the car before you permanently damage a cylinder or the catalytic converter. A good rule of thumb is to replace spark plugs every 30-40k miles and coil packs just as frequently. In some cases, these items are particularly subject to failure when upgraded software is installed, particularly because the demand and stress on these parts is increased significantly. Replacement as preventative maintenance also never hurts.