I have the exact issue as billgti. it also improves a little with the a/c off but this is not just the slight change when the compressor kicks on, its more like a classic car with cams. a little bit of a shake...
I wish i knew because my car is out of warranty so i am trying to avoid the stealer. The vibration goes away as soon as your foot is on the gas.
hopefully someone will chime in that has gone through this before.