F430 Exhaust Info

There have been a lot of posts about possible exhaust upgrades and about the sound of the F430. After probing around my car and seeing one today without the rear bumper mounted I can report the following:

The muffler and the tail pipe assemblies are made by a German company called Zeuna Starker which is owned by Arvin Meritor. At low speeds the exhaust flows out of the catalyitic converter cans into a transverse muffler box which by the way is about half of the size of the one on a 360. The gases then flow out of the box and into the outer pair of outlet pipes when viewed from the rear of the car.
There is a second set of outlet pipes that flows directly from the cat cans through the inner set of pipes at higher engine speeds. This is effected by a vacuum driven valve in this set of pipes that when closed forces the gases through a bypass pipe before the valve and then through the muffler, but when open effectively takes the muffler out of the loop. The vacuum motors are controled electronically
This knowledge would be useful to anyone thinking of purchasing a different muffler box because it is rendered ineffective by the valves.
In fact there is a marked difference in the color of the soot inside the inner and outer exhaust tips. The outer tips are dark colored and the inner tips are light grey colored.
This muffler bypass system explains why F430's have a much different sound than the wail of a 360. An F430 at WOT makes a sound which can only be described as an urgent bellow.

I think it's fantastic.