Originally Posted by BoilardZ

Not to beat a dead horse here, but I just wanted to confirm that replacing the window regulator (NOT the window motor) completely fixed this issue. Even though my car is still under warranty, I just replaced it myself, because I've heard horror stories about the dealership screwing up stuff when they try to fix things. I bought an exact-fit, brand-new, OEM regulator online for $60, which includes shipping and tax. It took maybe two hours to do the install. Even though the rattle was minor, it was driving me crazy. Totally happy with the result.