I got a free DC header for D series. The header has only one hole for an O2 sensor...I have a 96 EK hatch and it has two O2 sensors on the stock header...I know if I have put the header on I have to get a cat converter because the stock cat is on the stock header....But where do I put the other O2 sensor, do i drill a hole into the header, or can I make the two O2 senors into one...If I drill the a hole into the header, where do I drill it...What other options do you guys know....