Vibration at idle ... I know it has been discussed

[vinzer]

Hello all,

I am lucky owner of X5 E53 2001. I was reading this forum for a long time and was even posting some stuff here. I found extremely many useful info here which helped me to save a lot of $ and fix many problems by my self.

Recently (3-4 month I think) ago I start to feel vibration while at idle. Vibration happens only when I am on D or R and holding my leg on the Brake pedal. Vibration goes over all vehicle, I can feel how seat vibrates and steering wheel also. With the time (1-2 month) vibration become stronger.
First I assumed that this is Engine mounts. I bought two new mounts for engine and changed them. Nothing changed Still vibrating as hell. I did not change the mount of transmission. But I do not think that it will help.
Yesterday I checked my RPMs via OBD port.

While on Idle and shifter in Park position: 770-790 rpm (no vibration)
While on Idle and shifter in Drive position: 705-715 rpm (vibration present)
While on idle and shifter in Drive position and I put RPMs to 795-815 rpm - almost no vibration present.

Here is a question - my RPMs are normal ? or too low ?
What else would you suggest to check - idle regulator ? transmission ? rear engine (transmission) mount ?

Thank you in advance for any suggestion. Also I want to know if any one was having similar problems and found the way to fix these ?