psuLemon

i am thinking of replacing my obx header with a hotshot header and from what i hear, the hotshot header is the shit and thats why im upgrading, but my question is about the second O2 sensor that has to be relocated. since i had two cats my car has been throwing codes and its because im suppose to relocate my 2nd O2 sensor behind my cat. i have a magna flow high flow cat in there, so should i drill a hole in my piping and weld the O2 sensor in there or what should i do... i know random tech makes a cat but from my cat back it is all welded up so it wont fit... any ways in installing the second O2 sensor...