Saw this on the z06 forum and wondered how it applied to us.. Discusses the accuracy of a post exhaust wideband vs. the O2 sensor...

http://www.z06vette.com/forums/showt...threadid=27193

 

2 points make that test invalid for our purposes. First he put the WB 02 at the tail pipe even though he still has a catalytic convertor(s) installed on the car. This skews the readings of the WB. Second their cars are NA and are therefore likely to be running closer to stoich. Narrowband O2's (like the OEM) are very accurate around 14.7:1 but very inaccurate in the ranges we're concerned with.

*EDIT* - I read some more of that thread and it looks like the Z06 guys realize that his test was invalid too. They do run much leaner than us, they are talking about ratios in the 13.x:1 range, we like things a lot richer than that, like 11.5:1.