I decided sometime ago to sell a UK Reg bike and use the money to register in Portugal another bike I imported from the UK. It's a 78 CB500T and the process is tedious and time consuming, so decided to hire an agency to take care uf the burocratic part of the process.
450€ and a month later , I travelled 130kms north for the stupidest test.
They run the bike up and down an air strip (with my petrol) measuring the noise in 2nd, 3rd and 4th gear. This might seem very 21st century environmental bulshit, but no one really cares about it, it's just another OK stamp in the file.
This test cost me 150€ plus 20€ in fuel and a full day out.
It would seem I'm importing a bike from Mars but next step will be a 90€ drop and another 400kms drive with the bike on a trailer for someone at the "Classic Car Club" to give his thumbs up for a period number plate. In total its going to cost me more to register the bike here than what I paid when I first got it.
Try to remember this before cursing your import laws.