Once more thing about the LXI.  Every place I took it said that on diagnostics, the O2 sensors would right away switch it to a lean mixture.  They said it was in the "normal range", but that it was on the very low end.

Is that normal for these cars?  I had to get a new exhaust manifold becuase the old ones were warped and leaking.  Could the lean running make it run hotter and over time warp the manifold??
Once again, no codes or CEL.

just wondering.  Thanks