I was installing a pitch stop mount and since the intercooler was off I thought it would be a good idea to also upgrade the oem couplers from the intercooler (90 degree and throttle body). I used the grimmspeed coupler kit with a new BOV gasket. Today I was cruising down the highway in 6th when i noticed when i gave a little gas to about -2 psi of vacuum a whistling noise (like a tea kettle) started coming from the car. It was faint but very high pitched and stayed as the boost climbed. The car is performing as normal and boost is climbing ok with a steady idle. Any ideas about the whistle?? Small boost leak??