Aluminum/billet is what I recommend. There are some "shorty" antennas that are even flamed & colored. I got flames in the color to match my two-tone paint job. But - probably suffer a "little" on reception.
Chrysler PT Cruiser Exterior Accessories and Aftermarket Parts
Shorty Custom Antennas
StylinTrucks.com Billet Antennas by Shorty