The standard F430 delivers 490 bhp and the Stradale is believed to have at least 520 horsepower and about 220 lbs less weight. The biggest visible change are the exhaust pipes that got moved up a bit, producing an impressive soundtrack. The microphone that is visible at the exhaust pipes in the photos is there to help Ferrari make it as loud as legal.
I wonder if those are straight pipes? The normal F430 sounds amazing. I can imagine how this one must sound. Look for the F430 Challenge Stradale in your local Ferrari dealership in the beginning of 2007.