if the spring tension is very high.. with high amounts of boost.. the BOV will open and close, open and close very fast.. or a turkey call..
if the spring tension is very high.. and low amounts of boost.. the BOV will NOT open, and the turbo surge will result in a turkey call
if the spring tension is very loose.. and high amounts of boost.. the BOV will open and stay open for quite sometime and will close slowly... so letting off the gas, and mashing the pedal immediatly will not build boost. also too loose, will BLOW the valve open under boost, and you will have boost leak
Capeesh?