Hey Miles,
Check out this thread for tips on getting better audio. Unfortunately the Pre Amp that I recommend has been discontinued. You might find it on clearance at your local Radio Shack though.
http://www.northamericanmotoring.com...hlight=lav+mic
re: Rattling
Could it be the lens cap? Or maybe the headrest itself? When I experiemented with headrest mounts, I found that the headrest itself wasn't a rigid mount. Although maybe putting a several pound camcorder on it helped weigh things down, but when I put a VacuCam that weighed several ounces, it just bounced around a lot.
