I have a 2004 grand prix gt it started to vibrate on the hwy about a week ago. It has 152,000 kms. I replaced the cv axle at 117,000 kms, Bearings at 135,000 and I have michelin Hydroedge tires with 65% tread left. I also just did the breaks last week with new rotors and break pads. I had an alignment at 125.000 and the tires balanced at 120,000. The vibration isnt horrible but it is annoying. I was just wondering what it could be? Any help would be much appreciated. Thanks in advance.