I just bought a 2003 Z4 with DINAN aftermarket equipment. Arrowhead BMW (Glendale, AZ) tells me that BMW corporate required a car to be "detuned" to OEM specs before it can be sold by a BMW dealer. Anyone heard of this? I do know that the air box and exhaust are DINAN and there is a badge on one of the shock towers with "DINAN 5" on it. Exactly what does this mean?