Has anyone ever did this? I read you can insert the O2 sensor into a non fouler plug and re insert it into the O2 sensor bung and it would trick the O2 sensor by keeping it out of the direct path of exhaust flow so your CEL would not come on.I have read several articals that swear by it but need to hear it from you guys. 
Oh,This is to solve the problen of high flow or no cats.
Subaru owners swear by it.
Yup done it to my Civic back in the day
I took the o2 sensor out and put in a resister.
It's known in the Subaru world as the "$5 fix". I did it to our Forester, and it sorta works...I still get a recurring CE light with the cat converter code, but it will go weeks instead of days now. 
I don't know that it will work for a completely removed catalyst.
My solution to the CE light is now the $7000 car upgrade. 
Worked fine on my Evo VIII. Some really built Evos use a modified two non-fouler setup to get the post-cat O2 far enough out of the exhaust stream to be clean. It definitely, definitely, first-hand experience WORKS. No fouler on the pre-cat O2, fouler installed on the post-cat O2.
I only used one non-fouler, but here is the how-to for using two, and an explanation of why it works.
Non-fouler how-to.
Hope that helps. 
The Volvo guys use them on the post-cat sensor too. There are O2 sensor-specific pieces you can buy (don't require drilling the hole out.)
Yep, I've done it on a Civic with a failing cat to pass inspection. Works fine.
I've done it, works great.
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