are all saph cosworth vin number ment to start in 'BFGC'?????????? i read it in a mag saying that all saph cos are ment to start in that prefix...... however mine starts in 'WFOF' but ive got stacks of history with the car, hpi is clean as a whistle and the 1st MOT cert was in 1991 and it states that numer too also stating 'car type - sierra RS cosworth' what do all yours start in?