Audi AG is a Germany-based inventor and producer of automobiles. It manufactures Audi models such as A3, S3, TT, A4, S4, RS4, A5, S5, Q5, A6, S6, RS6, Q7, A8, S8, R8 and Lamborghini. In 2008, Audi AG enhanced its model portfolio by adding TT TDI, TTS Coupe and Roadster, A3 Cabriolet, S3 Sportback, Q5, Q7 V12 TDI as well as successor models to A4 Avant, sporty S versions of A4 and RS 6. It also produced R8 TDI Le Mans, Q7 V12 TDI coastline, A3 TDI clubsport quattro, A4 TDI concepte and A1 Sportback concepte. The Company operates worldwide through its fully consolidated and non-consolidated subsidiaries, such as AUDI BRUSSELS S.A./N.V. in Belgium, a part of the manufacturing network; AUDI HUNGARIA MOTOR Kft. in Hungary, which develops and manufactures engines for Audi AG and other companies; Automobili Lamborghini Holding S.p.A. in Italy, which produces Lamborghini Gallardo and Murcielago; and quattro GmbH in Germany which produces sports cars and customized Audi vehicles, among others.