I have exactly the same problem. It makes a "bok" sound on some bumps sometimes - I couldn't really tell if it was the left or the right. I also notice it sometimes when turning the steering wheel.
I also notice something stiff in the front suspension when driving over road humps - none of this behaviour is consistent however, and it doesn't bother me enough to take the car in for servicing just yet (I'll leave it till the next major service).
I have seen previous posts about this and I understand there is a fix for some early models - apparently a defective part in the front suspension...
