You would... from bits hitting the undercarriage to metal cooling and expanding/contracting... such is the life of an aluminum/carbon-fibre bodied racer for the streets...
I hear what your hearing. Got to admit it seems like it might need some more tuning. The bog between shifts sounds like its running a bit rich, although it doesn't appear to be blowing black. Yes the CSL has no sound deadening, but how that would affect engine noise from the outside is beyond me. Am sure Pat you will inform me....................
The lack of asphalt sprayed on the undercarriage will amplify the sound of things being thrown at it rather than isolating it. Noise INSIDE the car comes from noise OUTSIDE the car, remember...
They have removed the sound deadening material from inside the car, not the asphalt spary on the undercarriage. If they did that the car would rust in a year. Check it out, it still has the apshalt spary.
Thats no racecar. That does not sound like rocks and road crap bouncing off the chassis, I know what that sounds like. I don't care how much sound insulation material is, or isn't on it.
I have to agree, it sounds nothing like rocks being kicked up onto the chassis. Regardless, pretty sweet E46.
Double-galvanized steel and aluminum (which the chassis is largely made up of) would rust? EDIT: I don't really care, it's detonation.. not possibly anything else. It's your first reaction and there is no other explanation! Yay!