is it mandatory to use a torque wrench when applying the spark plugs??
i usually just install it with a regular spark plug wrench, is this damaging
anything to my car? thanks.

 

you dont need a torque wrench... just dont tighten too much and you should be fine

 

it goes like this. that little washer at the end of the threads is gesigned to be crushed. generally, and i use the term loosely, you run the plug down till it has resistence then 3/4 of a turn more will crush that washer. thats what it is there for. and thats it. use never seize if you wish.