Why do you want the wheels on your car torqued to the proper specification?
1. If the lug nuts aren't tight enough, they come loose and the
holes in the wheel "egg" out and then the wheel falls off.
2. If the lug nuts are too tight, it stresses the wheel studs to the
point of breaking and the wheel falls off.
3. If the lug nuts are too tight but don't break the stud, they are a
bear to get loose on the side of the road when you have a flat.
Impact guns don't know when to stop. The technician guesses when the nuts are tight enough. Torque limiting sticks used in some shops wear out, and are not reliable.
Request that the lug nuts be torqued to specification with a
"Click" style torque wrench so you know the job is done right.