I just purchased a 1998 Z3 - this is my first BMW and my first convertible. The top is showing some wear, the rubber strip around the back plastic window is coming loose, and water leaks on the top front of the windows. I'm thinking the top may need to be replaced, and I'd like to hear opinions and experiences. Should I go to a BMW dealer or somewhere else? I'm also looking for a good BMW mechanic (not a dealership) in the Dallas, TX area. Thanks for your help.