I removed mine, I think they look great and everyone thinks I paid for aftermarket wheels. The center caps that I bought from Metro toyota online just snap right in I think complete the look.
I have a 08 touring, I used electrical box cut out covers, they can be painted but I just left them as is. They have tabs that can be bent out a little to make a snug fit. I think they were 2 for .99 at lowes. If I remember correctly it was the 2 inch size.
Cool, will try to locate those... I asked my stealer and he quoted 22euro (~25$). I said for the 4 of them? Nope: a piece... And @Metro: do you ship to Europe?