Well, unless the sound suddenly gets a lot worse, or you can start feeling it, I wouldn't stress over it. One thing you need to keep in mind is that in the case of flywheels, there isn't a simple correlation between the way it sounds and whether or not it's functioning correctly. I upgraded the flywheel to a JWT lightweight flywheel in my 350. That thing sounded AWFUL. I mean, from outside the car especially, it sounded like something was broken! But nothing was broken. It was functioning just fine, and the harsh noise was a simple byproduct of going lightweight. We're accustomed to thinking that something's wrong if it doesn't sound good, and 99% of the time, that's how things work. But flywheels are one exception to that rule. Bad sound doesn't necessarily equate to bad function in the case of flywheels (which is what I believe is causing the sound). So stop stressing and enjoy your Z!
