Interestingly, some high-tech spark plug wires can provide an alternative to the Plasma Booster to accomplish the same task of increasing the intensity of the spark produced by the spark plug and thus provide the same benefits.
The Nology company makes a set of spark plug wires that each incorporate a capacitor and separate ground connection. With this addition, the spark plug wire itself stores up the energy of the spark until it reaches a high intensity level, then releases it in a shortened burst that provides a quick, clean ignition of the fuel/air mixture.
The manufacturer claims an increase in spark intensity of over 300 percent, which measurably increases horsepower and mileage, and reduces emissions by providing more a complete burn of fuel. An added benefit is that the substitution of the high-tech spark plug wires is legal under California Air Resources Board regulations.
Great information can be found here: http://mini-cooper-parts.blogspot.com/2009/09/high-tech-spark-plug-wires-for-your.html