Hey Guys ive got an impreza 95 plate which has a loud whistle when boosting. It only happens when driving it and the boost/turbo winds up, there's no exhaust leak, could it have a pipe leak on the inlet side of things? Any light on the subject would be helful

 

Boost leak. Probably a loose jubilee clip or split pipe.

Check all pipes too/from the turbo and also pipe from the tmic to throttle body and in and around the tmic.

 

Adios Turbo, boost leak will give running probs. Sounds like the T is on the way out