This is false.

SUVs need to meet emissions rules. Mileage rules are applied to automakers for the average of what they sell, allowing them to sell high and low mileage models as long as they meet the average. For federal EPA standards, SUVs and sedans both need to meet the same tier 2 requirements, and of course California applies stricter rules to both.

Perhaps you were thinking of the old tier 1 requirements, which had different rules for SUVs? That's two decades out of date. Since 2007, when the transition period ended, the much stricter tier 2 EPA requirements apply equally and make no distinction between SUVs and sedans provided the car weighs less than 8500 pounds. The largest SUV on the market, the Mercedes G Class, weighs 6800 pounds. The average SUV weighs about 5000 pounds, so no, they aren't dropping 5000 pound engines in them.