Yeah i went threw three different spring first I had the q 10 psi check engine light then I the original 7 psi spring again the light so finally I put the original 11 psi had no light was a bit to stiff cause I couldn't hear it on wot. I cut 1 coil off and now it works perfect no flutter,surge just a loud whip of air at wot.

The ital bov is the best bov on the market but finding the right spring is just trial and error but once you find the right spring It works amazing holds all the boost and sounds great very unique sound.I also noticed the q sounds different then the original less surge and more of a pure whip sound instead of a space invader which is more of a surge sound.