According to these sites, http://jalopnik.com/399551/new-set-pics-from-transformers-2-show-audi-r8-buddying-up-with-corvette-concept
http://www.zercustoms.com/news/Audi-R8-in-Transformers-2-Video.html
the upcoming Transformers: Revenge of the Fallen will feature a 2008 Audi R8 (Typ 42) . So we can start with this listing
(IMDB link http://www.imdb.com/title/tt1055369/ )