Denso will hold up better to lead (from what I hear) but its not a very active sensor. Bosch O2's are FAR more active and can deliver more o2 data, much faster to the computer. People havent had much luck with Bosch's and lead, but theres no telling how carefully they were installed. You have to treat every o2 like a thin sheet of glass when installing it because thats basically what you're dealing with. Just tapping it a little too hard with a wrench will affect how active it is. I had a new denso in mine when I bought the car, but had to replace it within 1000 miles because it was just dog slow on the o2 crosscounts. I threw in a Bosch and it started cycling 0-255 within 10-15 seconds, vs 90ish with the Denso. A faster sampling rate means the computer has faster control over fueling when conditions change. Its 50,000 miles later and I still have the same sensor in there. I use alky, so I dont have to worry about lead.
Another good thing is that its not even a heated sensor, but it's actually MOST active when the engine is cold. Cycles in like 8 seconds. It conducts heat to the element so fast that it doesnt need to be pre-heated.
