If you have a durmetic tool check out the cam 1 and 2 deviations. This is an indicator of potential ims issue. I posted on this in one of the forums as others have. I have an 04 with tip that I bought this year and originally worried about it. But after checking the cam deviations several months in a row where the phone were rock steady. Decided to worry less drive more. There was a very nice article by Mark Jennings about using sound vibration analysis to detect ims issues as well. He pointed me to using the cam deviation values. This is well worth reading. And can be found here
Good Vibrations