At the recent Northwest PT Event, Mossyrock, WA, I found a guy that makes quality center caps for PT Cruisers. They come in assorted colors with various logos such as "PT", "GT", etc.--whatever you want he will make and ship them to you. Since he couldn't match my Seamist Green paint I ended up getting them in "Electric Blue" with chrome "GT" logo. [8D]
I have been looking for sometime now trying to find high-quality and rugged wheel center caps for my GT--these are it!
They have rounded edges and look much like the caps on the Dream Cruiser Series 2. IMHO, they look great, and, if you put them on properly--above 60 degrees, clean and dry surface with alcohol, select area, peel and stick--I don't think they'll ever come off. I used a hair-dryer during installation which just made the self-adhesive work that much better. A set of four is $20 and you can purchase extras for $5.00/each. They are available from Casey Carlson, Manager, Auto Trim Design & Sign, Lacey, WA (Phone: 360-236-8852).
http://www.autotrimdesign.com/