Whooshing on the boost is usually due to an intake vacuum leak from a loose hose or clamp.  The clamp or hose could be secure enough under vacuum to not cause any problems, but once under turbo boost, it opens up to release some of the pressure.  If you have an accurate (aftermarket) boost gauge, you might notice less boost than normal.

Please check our intake vacuum leak page for more info on possible boost leak areas:

Questions?  Comments?  Send mail to:  reted@fc3spro.com