hey i see a lot of us not knowing what spring to run in the BOV. most every one is saying green but for some of us green is leaking off a lil boost at 21, 22psi. BUt i see for a lot of the other forge bov's they make shims to fine tune the spring you are using. it look like a shim with the green spring would work best for all of us tuned. Cause the yellow seems to hard and the green is just a lil soft for when we are switching over to sport mode. 1 shim would make the green spring hold to about 25psi. i am going to call them and see how to get a hold of these "shims"