Clearly you have NO IDEA how companies work. These amounts are the tax you will pay if you pay yourself a salary and buy a car with that money.
What you actually need to do is setup a company in Portugal, get 100k in the company, buy the used car with companies money 80k, spend some money on accounting, smallest salary 1k/month. At the end of the year you will have:
1. car you want registered at your company (not your private name), with local plates.
2. salary (small but salary), social insurance, pension fund
3. you'll pay the income tax on maybe 5k remaining in your company
It's simple as a pie.
If anyone asks you︀ anything - you own a company, you pay yourself salary, pay corporate taxes, you pay︁ social contributions, and the car is company's car and you have a right to use︂ it.
Very simple stuff...
Also WAAAAY much cheaper than any Cyprus/Giblartar stuff mentioned.
Also if︃ your company is VAT registered, you can deduct that 23% VAT on many things you︄ buy. Just find a good accountant.