K03 audi A4 B7 2.0L TFSI 06-08 (k04 upgrade)Genuine borgwarner K03 turbocharger for 2006 8 tfsi 2. 0L audi A4 A5 Various upgrade levels available, all a direct bolt on turbo withall housings bored out for larger impellers: Stage1 300hp 41. 6 mm Stage2 340hp 44. 3 mm Stage3 360hp 45. 1 mm Stage4 400hp 46. 4 mm billet wheel. The upgraded turbos will work on an otherwise stock car but in order to fully exploit the full potential of these turbo upgrades, ecu tuning and HPFP upgrade are needed.