Who is going to buy the Lamborghini ? Wetsuit has done a good job by hiding his/her identity and once you walk into a Lamborghini dealership, all anonymity is gone. They will have to do a transfer of ownership and also a lot of paper work to finalize this purchase.

Will you arrange that the "winner" deal directly with the dealership and paper work and then only do the final payment when the "winner" is invoiced to do the payment?
The actual purchase process might dox either the winner or the owner of Freebitco.in.

Not a problem. Assuming the winner doesn't hail from US and the costs outweigh the benefits, wetsuit could just reward the equivalent sum in BTC.
Plus, noone knows where he's gonna buy the Lambo from unless they rather waste time and money tracking down the exact dealership and salesperson. Not worth it IMHO.
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.
Large amounts of money attract attention from the IRS and also Banks, so this is not going to be an easy task to do this without compromising your real identity.