Impact wrench can overtorque your lug nuts.

Be careful about using an impact wrench to tighten your lug nuts on your car. Most mechanics routinely ignore manufacturer warnings to use a torque wrench when tightening lug nuts. Most will use the impact wrench because it is fast not accurate. More is definitely NOT better with torque. You can over torque your lug nuts and damage the studs. When the nuts are tightened, the studs will stretch. This tension holds the wheels on to the rim. If you overtighten the studs you can damage them and they could fail. They best approach is to use an impact wrench to snug up the nuts. Then go back with a torque wrench and tighten them to the manufacturer specifications. Proper air tools make all the difference.