I changed my O2 sensor on the 4th of July(God bless America) and although the how to was vague, it made a difficult job easy and painfull. My forearm is still swollen from jamming it down between the engine and firewall, but it only took an hour and five minutes. That time included talking to my nephew and taking a soda break inside the house. I'd have to say the next time I could probably do it in a half hour, no kidding. However, I hope I never have to again.
In any case, thanks CEG and thanks how to guy.