Based on all the discussion recently about Bosch automotive products, I've begun searching the forums about reliable plugs, wires, and O2 sensors.
No one has anything bad to say about the AC Delco sensors. Surprisingly, my local GM dealer gave me a 25 percent discount on my aluminum-framed LIM gaskets (I didn't argue or ask why, naturally -- maybe I was wearing my Kevin Harvick hat). So you never know sometimes who'* cheapest. Don't delay too long at the expense of your car'* performance.
Several members have been trying Denso. The verdict doesn't seem to be in yet, but I couldn't find any complaints. (I see Lash has some favorable comments about Denso, while I'm writing this)
Most Bosch users were unhappy. It seems their O2 sensors work well for about a month and then poop out. The 3800 engine is apparently too tough on most or maybe all Bosch products. I don't think there'* anything inherently wrong with the Bosch products (they work well in my motorcycles), but they should probably be avoided for our kind of cars.
There are members that really like their Bosch equipment, but they are in the definite minority.
Given the importance of the O2 sensor for good gas mileage and good emission control, pop for the best sensor members suggest. Any dollars extra will soon be made up. And you may pay less than you think.