This mod helps the hotair cars even more than it does for the intercooled cars. the inlet diameter on these parts is more than .300" larger than the exit diameter. (65mm vs 57mm) Plus there is an even smaller lip between the two sections and two IAC tubes that protrude into the airstream to further restrict air flow. The mod I do involves Machining about 5 mm from the rear section and removing the lip where the two diameters meet, I then grind the IAC tubes flush and modify the shaft to improve airflow.