Lowering new C8 - ok to do it immediately?

[DAL]

I would ask my actual insurer underwriter (not the broker) before anyone else ...
as the start of questions on 2nd year renewal may include ...
"any modifications"? You will only regret not asking them
if an adjuster ever stink-eyes during a claim.
Next would be GM warranty including the extended warranty
underwriter as some "away from factory" modifications can throw coverage aside.
Even though if lowering is mentioned in the manual ... it never hurts to make sure.

Not sure about everyone else’s experience, but I have modified almost every car I have owned and never, ever, had an insurer ask or care when making an unrelated claim. Merry Christmas.