My 220d is my first mb, so i don't know how the 330sd is constructed. On the 220d there is a bracket a couple feet rear from the exhasust manifold. If that bracket were loose the exhasust pipe might slap back and forth making noise. Did this problem arise immediately after swapping out the old brake system? Did you overtighten the wheel bearings? If overtightening the wheel bearings this would reduce bearing / race life, but it doesn't intuitively seem it would result in the noise you describe under those conditions. I mention the exhaust bracket, as this would be consistent with hearing the noise while pushing the car from side to side. It sounds as if a relative movement of drive train to chassis is the problem. The exhaust suspension system problem would be consistent with this and the most easily checked..