What vanos codes are you getting? That will really help pinpoint the issue.
The sounds that you are hearing could be normal for direct injection. My 335i was noisy as hell and it always worried me. My 135i sounds the same as does my friends 335i. All of these cars have had the vanos solenoid's replaced. We were throwing vanos codes after hard pulls.
RB EVO - Best ET: 10.9 | Best MPH 133.4
BMS - Fuel-it - MFactory