Ok, so I have a 50mm Tial BOV installed and currently have the pink spring in it. Also have the unpainted one I can install. Under high boost it operates properly, relieving the pressure. My problem is under mid boost, like 10-15 psi. I can't even roll out of the throttle without the thing going crazy, causing surging and bucking. If I quickly pull my foot off, everything is fine. It's almost as if when I slowly pull my foot off the BOV switches between open and closed rapidly. I assumed having the stiffest spring would keep it shut except when relieving high boost and we didn't want it opening every time we reduced the amount of throttle, for instance when merging on to the highway. Give it some boost to get up to speed and then back off the gas a little to keep moving. Anyone ever experience this or have any suggestions?