V8 Exhaust Noise upon Heavy Acceleration

Wondering if any other V8 owners out there have heard this noise. With your window rolled down (to hear better) and upon heavy acceleration - floor it - at about the time the tranny would shift into 2nd gear I hear a rattleing noise coming from the exhaust system. Sounds like a quarter rattling around inside of a tin can. It lasts until I back off of the accelerator.

Here's the kicker -

I just had it in for my 5,000 service and asked them to look into it. 2 weeks later - that's right 2 weeks - the dealer was stumped with the noise, so they called in the VW Service Head for my area. He simply stated that what I was hearing was "normal" exhaust noise for a V8.

Thinking that they were trying to pull a fast one, I asked to test drive a brand new T-Reg to compare and TO MY SUPRISE it sounded the exact same. Now, I realize that it may be "normal" from VW meaning that they all are doing it but it surely does not sound "normal".

Anyone else hear this noise???