I had an idea while i was at work to grab two packages of some spark plug non-foulers (you can find at any Help! section in an auto parts store) and on only two of then reem out the hole where the fouler is located so that you can screw your O2 sensor into it without it binding(i used a 1/2'' drill bit) and then double stack (or screw both of the foulers together) and insert it back into your exhaust pipe, and remember to put antiseize on the o2 sensor and non-foulers only one thing to remember is that the OEM oxygen sensors are larger then the aftermarket bosch sensors, so you may need further modification to make it work, but mine worked fine with OEM replacement parts this has eliminated my Catylist Efficiency code and it has not come back also remember to disconnect your battery cables because the bank 1 sensor2 is really close to the starter solenoid. i will try to get some pics if anyone is interested

 

Sorry but these:
http://www.o2sim.com/24803.html

are a hell of a lot easier than your "reeming" out anything.

$25.00 and 4 wires spliced worked great for my 99 vortec pickup. for 4 years now.