The Globe and Mail reports in its Friday edition that Detroit's automakers plan to tell the Trump administration that proposed changes to the North American trade deal could cost them billions and harm their competitiveness. A Reuters dispatch to The Globe reports that U.S. car companies are already struggling with last year's tariffs on steel, aluminum and vehicles from Canada and Mexico, while foreign rivals from Japan, South Korea and Europe face lower tariffs. Auto executives are concerned that proposals ahead of next month's talks with Mexican trade officials could increase costs. A key issue is Washington's demand for vehicles to have at least 50-per-cent U.S.-made content to qualify for lower tariffs. That requirement, as well as a proposal to increase overall North American vehicle content from the current 75-per-cent level, would add at least $2-billion (U.S.) in annual costs for each Detroit automaker. Those expenses would come atop costs the automakers already have been incurring from the various levies in place since last year. U.S. automakers currently face a duty of about 25 per cent on imports from Mexico and Canada, but vehicles with heavier amounts of U.S.-made content get lower tariff bills.