My Chrysler 200S hardtop NEVER creaked -- was as solid as a coupe with the top up.
Then again, my understanding was that the roof was designed back when they were owned by Mercedes by the same firm?
Will take to my dealer -- unfortunately bought it as a CPO from another state -- will see if they stand by it. For what it is worth, my Porsche 911 C4 convertible hardtop creaked just as badly...