Registering a vehicle in Spain

We shipped our US vehicle to Europe for a touring vacation (Spain, France, Switzerland, Italy, Belgium, Holland, UK).

We have amended our plans and will be staying as residents, so we are looking into the option of obtaining Euro plates.

Our country of Residence is Spain, - we own property there/ NIE / Padrons etc. We both are dual citizens (USA and UK) and also have valid drivers licenses in USA and UK.

If we wish to register our vehicle in Spain, what is the process, approximate costs and other relevant info.

I understand we will be exempt of the tax duty due to owning the vehicle for more than 6 months and having lived in America for more than 12 months

Vehicle info - Porsche Cayenne 3.6 V6 (2008) LHD, same emissions and spec as Europe, except rear light cluster (flashes red instead of amber)

Thank you,

Mr & Mrs Fleet