drop links wont affect the car's track, they would make a knocking over bumps and in severe cases a vibration and wobble under heavy braking.
when a car constantly pulls to one side (when driving at constant speed on a flat road surface) its often due to one tyre having more grip (less pressure, different tread pattern).
jack the car up and rotate each wheel to see if one seems to move more easily than the other. a quick spin of the wheels can show that one side has a stiff wheel bearing or a seized caliper or drum that can be easily overlooked.
here's an interesting link about how to test your tyres by swapping wheels around to idenitfy the problem tyre, i suggest you try it. its saved me a lot of time more than once in the past. http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=12
if the car pulls to one side only under hard acceleration that is normal (torque steer)
if the car pulls to one side when braking it suggests the brakes are not balanced, this could also suggest your problem when not braking is related to the brakes.