Re: Vibration while accelerating
If you are going under your car to repair this, you have to drop the exhaust, and remove the bottom shield to expose the driveshaft.
Then, remove the 4 front and rear bolts connecting the driveshaft and the 2 center bearing bolts holding the center bearing, and the 4 front bolts connecting the rubber guibo to the trans.
If you are planning on keeping the car, replace everything with new parts, the bmw dealer will cost about $1k for the driveshaft with center bearing.
The vibration may be caused by the center bearing rubber mount, or one of the U-joints, or the guibo connection. It is difficult to have the U-joints replaced and balanced, better to buy the whole driveshaft. The center mount bearing assembly is cheap, but you have to pull the driveshaft apart to replace it (make sure you mark both sides of the driveshaft for alignment during re-asembly), or, the balance will be off!!!