Ooof!
Is it taxed at the moment of purchase? Or do you have to work it out annually?
I personally don't mind slight differences in tax rates for different items, Lambos and Private Jets taxed at a higher percentage than milk and bread, sure... but what you're describing would drive me bonkers.
As it comes into the country. If it is over 100€ (maybe 150), it goes straight to customs and they won't release it until it is paid.