I'm not talking about IMPORTING a used unit, but BUYING a used unit. I wouldn't have to pay any taxes and warranty would still be valid.
Stop talking nonsense please. Taxes and warranties are not and never will be related. Period.
I think the main thing here is to separate imported goods from goods bought within national borders
(used or new). I think Ole understood you as referring only to an imported unit (per your example of importing a car),
then of course correct, if we both lived in the same country and you bought a unit off me you wouldn't have to pay additional taxes,
and any remaining warranty would be transferred.
If within the European Union, we could even have that same purchase without adding tax or customs charge.
As soon as you cross that EU border though, if buying from say Norway or the US, any goods regardless of age
would be taxed and subject to customs charges.
And again, of course warranty has nothing to do with from where a unit was purchased. The producer might have
opted to use a limited warranty, only valid within say the US and not transferable outside their borders.
They might then, or might not, have a national re-seller that will honor that warranty, but it is by no means
dictated by law that this must be the case.