I installed the new Denso O2 yesterday. The engine runs slightly smoother, but I will wait until I put a few miles on it to decide. I'll post some pics of the old Bosch versus the Denso later. The Denso definitely sticks out further into the exhaust stream and it also has more openings for the exhaust to travel through it.

It'll be more obvious when I post pictures.

Snowtoy, the shop never took a pre-cat reading, but I think Test 2 would be fairly representative of that. You could see right through the old cat. There were only a few pieces of the catalyst material left in there and they were all broken up. I know for sure the old cat was not working.