my car audio is probably a refurbished pair of NS10 😉
I have no EQ in particular but some genaral settings like none, rock, vocal, classic and i change them pretty often.
But mostly use"none" or "rock".
I am not "mixing" in the car but i am checking them all the time while driving.
I can recognize if my mix is too boomy and too harsh.
If it sounds good in my car, then everything is OK.