When you replace chassis with new you stamp the vin into the new chassis same as factory and keep a cut out of the old one . At least thats what I was told. No one bats an eyelid so long as the vin is stamped in the right place.
Using a puma chassis to replace your tdi chassis doesnt seem much different when you consider a replacement chassis from richards/marsland can be built to any spec you want. Mine is tdi front td5 rear.
Change a tdi engine to tdci is another matter. But I thought engine swaps were common, and not that hard to get approved if from same make and model?

