Seems like its from the rear...

 

Really hard to tell but sounds like the exhaust may be touching something. Get someone to powerbrake it sitting still. Should be able to replicate it that way. While it's making the noise, push down on each tailpipe with your foot and see if it gets worse or goes away.

 

Was hard to hear but it doesn't sound like anything major breaking. Soundls like an exhaust hanger or heat shield or something like that. Could be something in the trunk rattling around too. There are a couple spots on the side of the trunk where things can fall into and I had a golf ball bouncing around in there once and it took me a couple of weeks to track it down.

lift the rear of the car and get underneath there with someone on the gas and see if you can replicate it. You might have to put it in gear to make the noise too. Or bang around down there with a rubber mallet and see what rattles.

 

Check where the over axle pipes come over the panhard brace. They are bent to avoid it and they come within 1/2" or so. Could be touching the brace slightly under load. I had that the first time I put in my mid pipe.

 

Thank you all for replying. I appreciate the help and will post solution.

 

Crossing my fingers. I think it was the exhaust tip. Drove it twice. Last night and this morning completely cold. No noise after I took off the exhaust tip. Thanks again. Now on to the passenger seat.