I need some help in determining just what ITCS 17.1.4.C means as far as update/backdate phrases. My question is can you take (for example) a 1987 VW Golf that came with a 16v engine/trans. (hence ITA) and
install a 8v engine/trans. and make this an ITB car provided everything else meets ITCS spec ? I'm sure there are many other examples of this in other makes and models swap. Is this what substitution the ITCS is referring to ? (complete assemblies)
I also see reference to the VIN as determining " model and type for competition purposes". The VIN will also show engine size,trans type and a bunch more. Any insight will be much appreciated !

Tim