So im getting a noise in my Z now. It happens when realeasing the clutch and making a slow start. As im releasing the clutch and the car is starting to move, I get a weird, low frequency chatter, or grind (sounds kinda like somethings being dragged) It starts once the clutch starts to grap and stops once I get going. On quick starts you cant really hear it cause engaging first happens so fast. You hear it underneith, and a little behind you (thats where its SOUNDS to be) So im pretty sure its the tranny, but I don't know what. Is my clutch burnt? Is my flywheel damaged? Is it something normal that I just noticed at 13,000 miles?

 

I had something somewhat similiar, turned out to be a tiny rock inside between the rotor and the pad. It could be the same thing for you, take a hose and spray it hard onto the rotor and caliper.

It's possible the noise is occuring at higher speeds but the engine sound and road noise is covering it up.