I have a customer who is insisting on putting hotter plugs into his 1993 si coupe , his agruement is that he runs the car 13 hrs a day and wants a hotter plug for the car to perform to it's peak . I say that without a performance cam he is wasting money and at risk to doing damage to o2 sensors and valves . Without the extra lift form tha cam he is not expelling the hotter gases fast enough . What do you guys think ?

 

The only time u would want to put in a hotter plug than stock is if the plugs were oil fouling because of the need for a rebuild. 13 hours a day of driving on a hotter plug may cause it to fail prematurely. Hotter plug could promote detonation but on his stock motor, it probably won't hurt anything.