[compudude]

OK, the problem is still there. Here's some more info:

-Seems more pronounced on days when temperature is below 40 degrees.
-Very noticable high frequency vibration felt in gas pedal/floor boards, and seen in rear view mirror shake, between 60 and 75 MPH.
-I hear a rumbling noise from under the front when going 20MPH or slower (even in neutral).
-High speed vibration is there regardless of whether vehicle is in gear or neutral. Tested by coasting (in neutral) down a steep hill on highway at 65 MPH.
-Does not seem related to engine RPMs.
-Vibration started while still on OEM tires, and continues with four new Michellins.

This is really annoying, but beyond that I wonder if there's something about to fail that would not be fun to deal with at highway speeds..

Any thoughts would be greatly appreciated.

Thanks.