hey guys, my car started vibrating at 1400 rpm last week. I thought it was..... i dont know how you call them, the "supports the engine has", but they werent. I dont know what could it be.

Another question:
I fixed the head of my 520i, changed head gasket and all of that stuff. Should i drive the car in low rpm, is there any top speed until i do the second torque?
thanks and excuse me if its hard to understand my explanation.