I am Josť from de spanish Aventura Touareg Club. Good luck to all and hoping meeting you and sharing a great "aventura" together.
About the budget, yes it is money indeed. Just in tyres..........but I believe this is the cheapest way you can do it. Even a group of friends trying the same would not come much cheaper than this. Additionally we get an organization behind, with the arrangements, medical facilities, etc., all for a reduced fee.
All credit for those BWM riders going the whole way to Dakar. I wonder how are you going to cross the sand banks of Mauritania ............just kidding