Quote Originally Posted by Spartangl View Post
how have they been tested to be worse then stock?

and the Bosche spark plugs did better then when i had the NGK ones in!
If you are concerned about performance use the copper plugs when boosted.......(autolites are recommended by most) and the MSD coils have been tested to put out less voltage than the stockers...the stockers on our car are pretty much the best that you can get for them and most do not replace them unless going for looks or have something wrong with a stocker.