Unfortunately.. bringing a vehicle that's over 15,000 USD is considered as an import even if you resided in another country for several years and are coming back as an Argentinean citizen without intention of selling it for profits. Even if you were born in this country you can't bring your car after living outside for several years.
Before releasing the car into the country, AFIP will valuate your car and you will need to pay around.. 80% for it if the value exceeds 15 grands. In other words, if you paid for example your car at around $ 500,000 dollars, you will need to pay $ 400,000 dollars in taxes to be able to drive it here. I'm not going to mention other papers that you will need to fill and pay, because the amount won't compare to this, but.. if you really own a ferrari, leave it in the US or sell it there unless you have the cash to buy it again.
It's unbelievable that you can't bring your own used car because you basically have to pay it again in taxes, but that's how it works. Better to find this now than later. Please ask around to a professional that works in that line of business, but I'm pretty sure that this is what you need to pay for cars (not even 50% because that's for other categories). Here is a link with information:
http://cnnintl.com/C...t=520&width=750 (Duties / Taxes: Approximately 80% of car CIF value for normal cars, 100% for diesel cars and 65% for motorcycles. CIF price means Vehicle Price + Shipping freight + Insurance Cost).