Most of the responses assume that the winner will chose the bitcoins and not the car and that does not answer the question. No reputable dealer will allow anonymous payments I also doubt that Wetsuit somehow achieved the impossible to get a dealership to accept an anonymous Bitcoin payment for the car. 
It's actually quite easy to buy a car through an intermediatory. That's what https://www.moonassets.io/supercars are doing for example. They don't actually sell cars they just handle the Bitcoin to fiat conversion.
I think a lot of people who don't live in a country like mine where we have a lot of financial structures to help people do things don't realise that it's easy to do a lot of things via a third party now, as long as you're willing to pay someone a fee somewhere.
Bank accounts, buying houses and even islands. You can even use a trust to help you get your lottery money if you win lotteries and don't want to reveal your name.
