It's fair to say that the Spurs are better than many expected this season, so now the question of just how far they can go is a valid one. The postseason is almost a foregone conclusion at this point. Not making it would require a monumental collapse of identity or significant injuries (knock on wood). But their ceiling may come into question strictly based on unfamiliarity and lack of chemistry.
ESPN Insider Michael C. Wright raised the point in an article exploring the chances that the teams that seem to be contenders actually are what they appear to be.