I finally had the Berklee muffler fitted last week & can vouch they are a "great value for money mod". I only have the K & N filter with the Galant intake, lower resonator mod & engine cover taken off but this surpasses those easily. The muffler is quiet as well with no drone on long trips I just drove the car 2000km in 2 weeks on the highway and I am impressed you notice the difference when overtaking. I did not notice a difference in fuel economy though?