Depending on where in the engine, the Dual-Stage Intake Manifold sometimes whistles when you get up there.
My SVT Focus did that brand new back in 03 and then when I modified the intake and throttle body, the whistle happened at a different RPM and speed. Nothing to be worried about, just how the system works from the air.
Hatch Nation Member: #147
R.I.P - FELLOW FF MEMBER, IZZY, BLK2k3GTS, will always be remembered. We will compete on a different course again one day.