Highflow cat o2 sensor

My current cat conv.. is stopped up and i wanted to get somthing better than stock. Ebay has great deals on highflow cats but there is no spot for the o2 sensor. What should i do about the o2 sens.., Im planning on getting perf. muffler and one day get headers.

drill, a small hole and put it in

drill, a small hole and put it in :rofl:

Actually, take it to the muffler shop and have them weld an O2 bung for it. problems solved. They'll put in the necessary flanges while their at it.