I have a 2001 boxster s manual with the Bilstein PSS9 suspension upgrade. Strange problem - when I drive the car for over a half hour or so, it develops a creaking noise in the left front as the suspension moves; the longer I drive it, the louder it gets. Simultaneously, there is a slight resistance and squeaking noise through the steering rack right off center. Now the mystery - when I park it overnight, both noises are gone the next morning. Took it to my indie shop a few weeks ago for an oil change and asked him to look at the front suspension, but he found nothing (of course!). Any thoughts/suggestions?