Since he won the election in November, Donald Trump has used Twitter to criticize auto makers who build cars in Mexico.

Yesterday, in his press conference, the President-elect complimented two companies. He mentioned Fiat-Chrysler, which has announced a plan to invest $1 billion in US plants and create 2000 new jobs. He also lauded Ford, which now says it will put its plans for a new plant in Mexico on hold, and invest in an existing production line in Michigan. But he seemed to chide the other member of the Big Three, saying he hoped GM would follow the other firms lead.

Our motor critic, Sue Carpenter, says auto execs are treading carefully, trying to stay on the right side of Donald Trump, while also wondering what he policies may be, and how they could effect their businesses. Clearly, Trump's threats to place tariffs on goods imported from Mexico would hurt car makers. And his promise to renegotiate the North American Free Trade Agreement could complicate things for the auto business as well.

Carpenter also has an update on the VW emissions scandal, and a quick review of some of the more interesting cars being unveiled this week at the Detroit auto show.

Click the blue bar above to hear the full conversation.