Hey guys, I have replaced my previous 4 into 1 headers to a 4-2-1 headers, believe it or not the flow is way better and more responsive compare to the 4 into 1 headers. Before u can hear a boxster type noise around the car and more vibration with the 4 into 1 headers but now the only noise u can hear is right straight from the muffler no more vibrations aswell, my plan now is to put back again my twinloop muffler to reduce the noise, and by the ways u can hear the VTEC scream loud and clear with the 4-2-1 headers,