This is the first time (I think) we see/hear Clark call Luthor "Lex" (in the opening scene when Lois goes to edit her article). I don't remember Clark doing this either before or after this point.

EDIT: How were Lois and Lex traveling to go see Madame Butterfly? Did they take Lex's limo (as one would expect)? I can't see them taking a cab. If they took the limo, why wasn't Asabi (or another driver) suspicious when they never returned to the limo?

VirginiaR.
"On the long road, take small steps." -- Jor-el, "The Foundling"
---
"clearly there is a lack of understanding between those two... he speaks Lunkheadanian and she Stubbornanian" -- chelo.