There's 2 dyno's here in Stuttgart.
1. Schropp Farzeugteckhnic: They have a Superflow AWD dyno and by what i've heard is pretty accurate.
http://www.schropp-fahrzeugtechnik.de/usa_index.html
2.
http://www.speed-concept.de/ They have a Dynojet at the shop. I dropped 416PS at the wheels on that one last october. The owner is Steven. I can get you his number if you want it. He's a former 135i owner.