Driving Impression. The base engine is 2.7 liters and 185 horsepower with 184 pound-feet of torque. It’s smooth and meaty for a four-cylinder, but it carries too much weight in the Highlander, and the transmission is only a six-speed. Acceleration is reasonable but stressed if pressed. Forget it for towing, rated at a mere 1500 pounds. The V6 numbers match the best V6 engines in the class, starting with 5000-pound towing. The turbocharged Ford Flex and V8 Dodge Durango are quicker, but that’s not everything. You can hardly feel the shifts in the eight-speed automatic transmission, although it can be slow to downshift when you accelerate hard.