i was wondering if you guys could clear sum stuff up for me

[240s-sex]

i know that boost controllers change the vacuum/boost put out to the wastegate acutator but i was wondering about the springs...

tail 38mm wastegates (and others) come with different springs for different amounts of boost, my buddy has a 1.6 bar spring...which is about 23 psi

so my question is do these springs set a permanant boost level or a max or min boost level? also...if you have a car tuned to a cirtain boost....do you need to have it set to that psi/bar all the time?

thanks in advance...this has just been bothering me...way too many ways to alter boost