What the?!?!?!?!?!?
This is specific to Non-turbos. The port sleeves are referring to the 6-port's or auxillary ports. Removing the sleeves makes your 6-ports non-functiontal. This means you will have less low-end power. Removing the sleeves, MAY give a slight bit more top-end however. A lot of people do it, because they are tired of trying to fix their 6-ports, and they just don't wanna !@#$ with them, so they tie open the 6-ports, or go a step further and remove the sleeves entirely.


