first of all, you will never achieve perfect fuel/air mix so you have to choose one. i choose to run rich. true neither is good in extreme amounts but your car came from the factory running one or the other.

and second, before buying anything on e-bay just be sure to know what you're buying, just like if you went to your neighborhood speed shop. just makes sense to me. i would never buy anything for my car just because someone told me it was good for my car. when buying anything put a little research into it. in most cases you didn't come up with the money overnight, why make the decision overnight.