GrimmSpeed BRZ//FR-S Intake - Manual (Page 5)

7. Next, use your flathead screwdriver to loosen the hose clamp securing the stock
intake to the throttle body (figure 6). Also loosen the hose clamp securing the sound
generator to the factory intake tube (figure 7). Now, you should be free to remove
the stock intake system completely, including the sound generator assembly.