Bullydog GT you can up the idle or adjust the timing. If you don't want a BDGT you can ask the dealer to adjust teh idle set. don't know what they'd charge & it would have to be reestablished any time they upload new software to the ECM.
VG40DE engines have a tendency to have a little vibration at idle. Only way to adjust idle is with a capable scan tool or a tuner, like the Bully Dog or Superchips. There was also a TSB for vibration due to bad motor mounts, NTB11-014b. You can get a download of it here: