apache snow-FSO wrote on 04/11/13 at 19:18:37:Your mechanic is correct. The only thing these gimmick performance plugs do is separate you from your money. Well with a lighter billfold you may get a power boost.
+1 While some plugs may exhibit a hotter spark or a different pattern to the spark,they
will not in any way,increase horsepower. There may be a slight advantage due to a more complete burn of the air/fuel mix but that is highly questionable.
I hope they didn't get you for more than $5 US for that "special performance spark plug".