I am a new WRX owner and have put 20K miles on my 2011 wagon. Recently I maxed it out running with a CTS-V and now I have a loud hissing noise during boost. I have taken it to 2 dealers and both say that's a "normal" sound coming from the turbo. I am not crazy or stupid, this noise was NOT present for the first 20K. I suspect an exhaust leak but am not sure. Anyone know what it could be?