na NO2 on a car is fine... headers on a car? why not? But putting headers, body kit, sandbaging the back, 98 octane in the fuel, NO2, cool injected, supercharged, and adjusting the timing every evening... Thats a lil overboard... You could wait atleast a month before readjusting the timing
BTW NO2 isnt for every car.
Edit: Oh and racing slicks, spoiler, alternate batery for the speakers so that it doesnst tax the alternator and reduce rpm... (I could go on)