I have fitted the HKS Silent HI Power mufflet to my current exhaust. How ever i cut out the centre pipe. If you notice, from the inlet of the muffler, the size is 3in, 4 internal flow, how ever on the exit to the tip, its 2.5in with a pipe that runs half way through the muffler. I cut this out. Yes it made the car louder how ever, after changing from a cheap aussie made one, what a difference in noise. Cabin noise is lower, cruise noise is lower, WOT noise is louder though sounds alot better
h.
Note: i have no resonators or cat, straight throught exhaust with the just the rear.
h.