I believe the homologated process is part of the ITV when importing a car.
My own American truck cost 2500 euro's to import.
I purchased one that had been imported into the UK and had British plates and log book. And that was a pain getting it imported, even with a British log book, which should have made things easy.
Something to be aware of, is keeping the vehicle to factory spec. Any add on's to the car can cause a lot of unwanted grief and failures of the ITV. Things like bog standard wheels, no add on's such as bull bars etc.
To get an idea of what I went through going through the process, which took about two months with a lot of grief, check the following link
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It should give you a bit more insight
Importing American cars to spain 
