there is alot of vibrating which is why i feel it is low. my doors make alot of noise. also, periodically, my check engine light comes on but doesnt stay on long enough to get it checked out.

Hmm, that could be a list of things. Vacuum leaks, warn out engine mounts, tune-up ect.
At your at the milage, a lot of things start showing serious signs of age and wear.

I don't think there is a simple answer for your issue, only several things to start checking.

Suggest you check for error codes

Is this considered as normal idle (see photo below)? It’s just above the second line at idle in drive without A/C on. I have N62. With A/C on, my X is very smooth at idle but without A/C, I could feel slight vibration. 50 RPM increase would be perfect. I looked everywhere in DIS but couldn’t find the idle speed management. Can someone point me to right direction? BTW… Not sure what I did but my climate control remembers the last setting after I turned off the car just like my E46. I must have changed or reset something in DIS while looking for engine idle management. So the climate control is programmable unlike previous stated.

http://junger12.home.comcast.net/~junger12/Idle.jpg

You shouldn't have adjust idle to smooth out the engine. Something else is going on. Check for codes and if there are none then we can start troubleshooting.

It's always been like this since purchase. I don’t have any fault codes. My X5 is completely healthy from diagnostic. Vibration isn’t bad, just slightly felt from the steering wheel at idle without A/C on. With A/C on, it’s very smooth. I understand that V8s aren't the smoothest engine design but if I can smooth out by increasing 50 RPM, I would consider it as an upgrade.

Vibration when the engine is at idle could be a bad engine mount. With someone at the driver seat have them snap open the throttle with the pedal and observe the engine for excessive movement side to side.

I agree its probably the motor mounts, with 150K they are done. My daughters car did the same thing. The shift knob would make your hand go numb, I put new BMW motor mounts in and its smooth as glass now. I think it was about $200 in parts and about 2 hrs messing around in the garage. The motor sit quite a bit lower in the engine compartment before with the bad mounts and now with the new mounts it lifted it up about 1/2" and her air box lines up better.