adding catless header to a 2001

I am considering buying a catless header from a 98 model to put on my ride. I have a k&n filter, d&d pipe, and PCIII. I have read that installing a catless header on a vtec with PCIII requires power commander's O2 eliminators, is it the same with a 2001 non-vtec? Anybody out there have this mod on a 5th gen? What are the improvements? Any hit on mpg? This header does not seem to have holes for O2 sensors, I may be wrong. Any help would be most appreciated.
I just noticed that the wires going to both O2 sensors have been cut on my bike. It had been running like that for 20,000 miles so I am almost sure that the original owner had the pcIII programmed with that in mind. So the header should just be a straight bolt up, right? Do I need to alter the settings on the pcIII after installing the header? Help a viffer out.