I did find this article: Its doesn't completely align to the numbers reported on the news this weekend, but the gist (less than 1% cost impact) is roughly the same:
Ross, speaking in an interview with FOX Business’ Stuart Varney on “Varney & Co.,” said in a typical vehicle with one ton of steel, a 25% tariff would amount to 0.5% of the price of a car. That’s a $177 price increase for a new vehicle, based on February’s average transaction price of $35,444, according to Kelley Blue Book.
https://www.foxbusiness.com/markets/trump-tariff-threatens-to-boost-car-prices
I think a $150 increase in car costs isn't going to make much difference in car sales. Per KBB, average car prices have been increasing by 2% per year already and haven't seemed to drive any material impact to sales.
