Throttle body spacers really are a waste on V6 mustangs, especially the motivators or any of the ones that they say promotes swirl. Because of the fuel being directly injected into the heads there is no advantage in swirl between thw T/B and the plenum. All swirls dies. Now going back to the carb days when fuel and air mixed at the carb, a swirl device or T/B spacers actually provided for real gains.