i had my uppipe installed on my car and it sound like it has a leak,the shop that put it in said all wrx sound like that,so the next day i started my car and put my hand by the turbo and i did not feel any air ,nothing but it sound like it is comming from the top what could it be or is it just me thank you in advance

 

An exhaust leak will sound like a high pitched hissing. You might be hearing the turbo spooling. The turbo will sound louder w/ a catless uppipe b/c it doesn't insulate the sound as well as the stock one.