What's the build date on your car? Generally speaking, the first gear popping/syncro problem is found in cars built prior to Dec 2003. I would say take it to your dealer... although the 6-speed is on the clunky side, you should not have a problem downshifting into any gear. If they start to give you a run around... request a test drive in another car to compare the difference.

Good luck and keep us posted.