The little "box" on the intake tube is a whine baffle, along with the ones on the intake snout of the air filter box. They were put there to quiet down the whine, as when buyers bought these cars new, they didn't want to hear the whine as it was sold as a sport luxury sedan. Now on the other hand, we love to rip that crap off to hear the lovely whine of the M62.
Works the same way on alot of cars. My Dad'* Durango had a huge baffle box to quiet down the roar at WOT, but that changed when we put a intake on.