wont the computer try and maintain the idle via the aac valve, on a stock computer there is a small screw at the back where you can raise the idle preset 50 rpm or so.
Cost me $25 for bung and my local exhaust shop to do the welding.
My panel beater mate was enjoying burleigh heads at the time, so he cost me an extra 10er
Installing a wide band sensor in the factory O2 location will result in a shortened life span.
You will find plenty of useful info here... http://wbo2.com/lsu/lsuinstal.pdf
and here...http://www.techedge.com.au/
EDIT: not all WB equipment will allow you to simulate O2 readings that your computer needs so an O2 sensor may still be required.