I have not had to go through the process myself, and I know it depends on a lot of factors including engine size, emissions, value, how long you have been in the country etc but I think this process can be quite expensive even on a DIY basis. Mike has stated 271? just to change the headlights.
So I would think it must be worth considering - is it worth it?
ie say the process costs around 2,000 euros - then what would that buy?
It would buy an under 10 yrs old Mondeo (for example) plus sell the old car to recoup some of the investment.
Tricky problem, interesting that none of the companies who do it for you give a price range on their sites.