has been using it for 2 months in my peugeot 308. The main improvement I observed is my engine became much more quieter. I can barely hear the engine noise when the car is not moving, unless air-cond is turned off. The intercooler fan of my car (it is loud, pueugeot turbo owner should know it) spin less frequent, and gear box run smoother. I got a 10+k audio system in my car. I would say the tweeter smoothness improved a bit, not really noticeable if u dont listen long enough. I am hoping it to longer my battery life since peugeot battery average can only last for 1 year. FC not sure as I dint really pay attention to it. Definitely recommended to everyone. Good VS here!