Why does the XK sound different than the VDP even though they have the same engine?

My VDP sounds like a sewing machine, while the XK sounds more like a beast. Where are the changes? Is the exhaust or is the engine actually different between the models?

 

The difference is all in the exhaust. The VDP is a luxury cruiser so is its quiet exhaust tone. The XK was supposed to project a sports car image with its aggressive exhaust tone.

There is even a significant difference between the same 4.2 liter engine in my old '05 XK vs. my '08 XK reflecting the difference in the exhaust hardware. As I reviewed the MinaGallery muffler in a thread yesterday, the sound from the Mina is once again very different, something that I find more "sophisticated" than the stock XK.

Albert