You have to remember, 75% of tt.net consists of retards. Those retards are trying to be cool by saying anything but their way is rice. Anyway, I think it can be contributed by the configuration of the set-up. I have been in car's where the BOV goes off anytime the gas is touched. And most of the time he was not even in boost. Also all the vented air is going through 2 BOV's rather than 1(in most cases). So it is pushing less air through each BOV making them not as loud. That would be my guess.