^^^^ is correct!
the only time I have ever seen those spacers work is when the engine they are on has a "wet" intake.
"wet" intake means that the intake has fuel flowing through it. like with a carb, or TBI, where the fuel and air mix at the top of the intake manifold. with a wet intake, the spacer gives the fuel and air more time to mix.
most newer engines have a "dry" intake, meaning that there is only air flowing through the intake manifold. the fuel is injected basically right at the intake valve. with the dry intake, all the spacer will do is slightly increase the volume of the intake, and will do nothing at all to help the fuel and air mix. HOWEVER, you MIGHT notice a very slight increase in throttle responce(from the increased intake volume). in most coases though, the increase in throttle responce is so minimal that it's really not worth the effort of putting on a spacer.
maroon 1987 Grand Wagoneer. stock for now...