I recently replaced the struts in my 03 wrx with kyb gr2's. I'm really happy with the performance so far, but i notice a strange sound coming from the region near the left front strut. Sometimes when I go over a bump either going strait, or turning right (for some reason I don't notice it when I'm turning left) I hear what sounds like a knock on a glass window. Everything seems nice and tight. Also, I can only hear the noise with the windows rolled up. Anyone have any ideas? Thanks.

 

I would check the tightness of all the front control arm bolts and the condition of the front inner bushing and rear bushing, as well as checking the condition of the outer ball joints.