I have no idea if Strzok was living above his means or not. I would only say that this is how the arch-traitor and Soviet mole Aldrich Ames was caught and it was not in the act of passing documents to the Sovs; on an otherwise decent but not wealthy income as a CIA official, Ames had multiple high end foreign sports cars. If in the event that Strzok could be shown to be living above his means (and I have no idea that he was or was not) then it would make for a very interesting issue to investigate.
I was also thinking about Ames. And we know that lots of money has changed hands in this story (the “dossier”), so well worth investigating.