horsepower is rarely the limiting factor for a sedan's towing capacity. a sedan's chassis is only designed to withstand accelerating and stopping its own weight (plus a margin for safety and internal cargo of a reasonable mass). you could probably get away with towing a jetski with a typical sedan, but anything much heavier than that risks bending the chassis. even if a car can tow something without deforming itself, the change in weight distribution can make for a very unsafe situation.