how can i fix my 2003 vw passat turbo?

my turbo loses power mostly in the mornings when i switch my car off and start it again it goes back to normal i actually do think its a boost control problem. i was advised by one mechanic to get the turbo reconditioned. but then recently i was told if i replace the boost control valve this could cure my problem does any one know would replacing the boost control valve work?

cillian
August 2010