Clicking / knocking sounds from driveline when engaging clutch quickly in reverse

[psamtik]

2009 135i w/ 55k miles, replaced clutch 6k miles ago as old one was worn out.
Koni Yellow Shocks + HR sport springs

Symptoms:
- When engaging clutch somewhat harshly (and almost stalling out) whilst going in reverse, I hear clicking/kncoking, as though some mount is slightly loose. It's not alarmingly loud at all. It might just be my aftermarket suspension.
- Occasionally, when my clutch reaches the biting point (as I'm clutching out), I hear a few cyclical clicks. No idea what this is.

I have no idea what this could be. Something seems loose. Any ideas before I take it into the shop this next week?

[psamtik]

bump