Quote:

why are repo parts that have falsified date codes acceptable but altering engine/tranny information or even VIN information is strickly forbidden?



Mass produced “cookie cutter” parts are not governed or mandated by the DMV and the DOT. Vehicles are assigned serial (VIN) numbers that federally register the power train and sub frame to "THAT" particular vehicle. The alternator, tires, battery, etc…. are very similar to components that are used to construct a building. You do not need to amend or alter the title/deed when replacing door trim, hot water heaters, or roof shingles. Just like the alternator however, these replacement components need to comply with guidelines established by the building codes and industry standards. Printed “date codes” do not alter the function or performance of a part. They simply provide a way to know when, or from what batch, a component was manufactured.
Synergy….the whole is greater than the parts!