I had the same high-speed vibration issue when braking when I replaced my pads (Akebono) and had my OEM rotors turned. I know BMW does not recommend turning the rotors, but they were within spec, so I had it done.
Anyway, i'm not sure if it was a result of the rotor turning, or my aggressive bed-in process, but turns out the right front rotor was warped. I replaced both front rotors with Z4 35i rotors and the vibration is GONE. Good luck.
2007 SGM e90 335i, Spt Pkg, Prem Pkg & Nav
Mods: JB4 G4-Map 5, BMS DCI, 19" Reps on Hk V12s, SupremePower Lowering Perches, BMS Angel Eyes, VSFR DP & 5" FMIC.