Not the rowdiest, but certainly the loudest:

Kansas City Chiefs fans at Arrowhead stadium.

The visiting QBs complain of not being able to hear themselves yell their own calls on the field!

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car