Sorry if this has been posted before, but I searched and didn't found anything. Question for those who have the KTS suction kit: In the rear turbo piping there is a port where you screw a vacuum nipple in, what is this nipple used for? I don't recall having any vacuum port/line on the stock rubber hose when I removed it. What bolt size can I use to cap these port off? BTW, I have an R33 GTR.