Follow BMW on Facebook and twitter. Tag in as many post as possible until their media dept take note and push up the chain.
Also worth posting this in the USA section. They seem to get courts to force BMW NA to take action.
Contact senior BMW execs - get their details through LinkedIn..
Car: 2010 Jaguar XFR (Cat-back exhaust)
Gone but not forgotten: Highly Modified E90 335i LCI M Sport Manual (circa 480BHP/500lb ft)