You should hear the E92 V8 with said airbox!!!Hmm I like the engine out the box on the E9X M3, sounds all V8-y
But, big but, The S54 just sounds much more of a sporty engine with the carbon airbox, and arguably a bit louder/more vocal - just without the v8 rumble of course. And it revs to 8000rpm (mine goes to 8300rpm because of the Evolve map).