I honestly don't know if it needs rebuilding or not. It worked great when I took it off my car last season, so I don't see why it would. I don't know the base spring pressure I think its like 10-12 lbs but its capable of holding as much boost as you need . All you need to do screw in another "nipple" into the hole you see on the top of the housing just like the one sticking out to the right off the bottom. Using a "y" and a bleed valve routing air towards the top "nipple", it will hold the gate closed longer and therfore more boost. You just have to start with the bleed valve closed to get your base boost pressure and then work your valve open slowly to gain more boost until you reach your desired level.
