Do you guys know if there is any difference between the boch rotor & distributor sold at the regular parts stores and the boch ones sold at the dealer.According to this guy at the dealer I can not buy let's say a cap at the parts store and buy the rotor at the dealer.He said that they would not match perfectly because the ones made by boch for mercedes are specially design for mercedes.Do you guys know if that is true or is he just trying to make me spend the extra money at the dealer.