So i have an 06 polars 600 carb'ed turbo. It has an aerocharger 53 series. I understand the basics of basically shiming the spring to get more boost or installing a "stiffer" spring. There are three screws plus a nipple on the outside of the turbo hood, or where you get to the spring. I know what the center one does, what are the other two (brass) used for? Thanks for any input!