Not sure about the actual import process, but once you have it in Greece you go to the “τελωνείο” customs/DMV to “open” the car (typically costs about 100 euros) and I believe you can’t operate it for more than 6 months consecutively. At the end of the period you go back to “close” it, in which someone from the department comes to where you will store the car to note the mileage and put a wire from the brake to the steering wheel (I believe cost around 40 euros). It may make sense to convert it to Greek plates, but really depends on tax it would be annually to do so based on the horsepower, and how long you plan to use it.