This is what i read somewhere, i think zerotohundred forum, the O2 sensor reads from all four to send signal to ECU air fuel ratio. Plugged to only one might not give an accurate signal & might have adverse effect on the engine. It is suggested to use the original header & change the rest of the pipes, some sort of 4-1 setup. I still dont understand much though.

I was thinking of changing to highflow Catcon, but i read reviews that performance increase is barely felt.

wow..great stuff. Can you do a you tube video while driving? im curious to know the sound from inside cos im aiming for less noise.