Just got my '06 MPV LX and I'm looking to buy audio upgrades on eBay. Part numbers for various components on MazdaUSA site vary from model to model, but do have similarities. For instance, the 6 CD changer for the MPV has part number LD51-79-EGO. Other models have different combinations for the first set of 4 or 5 letters/digits, but some have the same thereafter, i.e., F149-79-EGO is the changer for the 2001-2003 Protege. Could it be that the first set identifies the vehicle model while the balance is part specific, i.e., all parts XXXX-79-EGO are the same and interchangeable?