For Z-Lab, I have a skeleton case that I can plug an external microphone into. I run an extension cable from the camera to the microphone (with foam windscreen), which is fixed to the floor panel by the right rear taillight where my singe exhaust comes out. It took me a while to figure out this arrangement to get rid of the wind noise and let you hear the engine on video.
Yes, Harris Hill is a *rough* track.
When was the last time you *really* did something with your Z to call yourself a Z enthusiast?