[GreyGhost702]

Sweet vibrations. I had a terrible "clicking" noise after firing up the car with the new build. Dealt with it 'til I had the engine break-in completed. Set the car on jack stands outside one day and fired it up so I could slide myself on a creeper under the car while it was running so I could locate the offending sound. Just go at it with a 12" socket extension touching virtually everything that looked like it might have movement. I did some small 1" x 1" square adhesive heat shielding as padding on the back sides of some of the metal heat shielding under the car, as I found they were "buzzing" a bit and this softened the connection to the chassis well and I don't have to worry about it melting. The clicking under the car wasn't as pronounced and had a really hard time hunting it down. I thought it might be the NPP valves clicking so I stuck a longer extension up there and didn't have enough effect. There's all kinds of heat shielding around the muffler area and connectors and shit, I still need to go over those. But as I reached my hand around the rear bumper to reposition myself I grabbed the edge of the license plate and the clicking stopped. So it turned out the license plate was vibrating with the cam. A touch of doubled sided 3M here and there, screw the plate back on, no more clicks.

Now that I have driven the car for a while and put a lot of WOT time on the car, I have developed yet another "chirp" I need to hunt and kill, but it sounds like a spring time job.

I suggest the same approach, get the car off the ground safely by whatever method you can so that you can get under there and touch stuff until you find the offender. You'll probably find things along the way that are making noises you aren't hearing in the cabin, as well. Heat shielding is often a noise maker when it picks up the right frequencies or you start shaking the car. Adhesive heat shielding is cheap (relatively) and will help dampen vibrations and is very wear resilient. You can slide this stuff behind cables and stick it to the chassis to keep connectors from vibrating against the car, all kinds of clever ways to apply it.

Your sound almost sounds like it's in the trunk itself. But sounds are a PITA to locate sometimes. I thought my click was under the car, and it was the damn license plate. You really have to feel around for it and molest your car.