Thats great that you are a retired customs official, the entirety of the legal system that classifies vehicles is sort of a joke in customs and excise - you already know that, you have taken a passenger hatchback vehicle and changed its wheel base, ride height, body structure - but somehow it will be declared as a "saloon" in the papers where the heading of horsepower ends in engine cc and is a poorly hand written document anyway
Custom cars come in two categories, coach build and one off - coach build used to be quite popular in the old times - its very expensive nowadays, the one off unique custom cars have a completely different structure of registration and road use privileges. Some countries do not even allow light hand built cars on highways as the "one" car was never put to a systematic test to determine insurance/legalities.
I fail to understand how you are determining this discussion went south?
