1151, no, have not done any thing more. I got a work thing that keep me busy for the last year. Put a lot of miles on the car, and am starting a clean up and detail. The trim rings are still on, and look like the day I put them on. They clean up nice. Spending a lot of time with the boat getting it ready for the season. Not putting much time in on the HHR. Though I did get the engine bay cleaned up. The stock air cleaner looks so silly, I had to get it out of there, installed a GMPP unit, that really dressed up the engine bay.
Try to get after the center caps this spring..........

 

I found this thread on a search, and I ended up getting these from Autoamenity.com. They look great! I just put them on, which was a walk in the park, so I haven't driven on them yet. Hopefully that goes well. I went this route because I hated the horrible noise the stock hubcaps made now that the good weather is here and I'm rolling with the windows down.

To further clarify, the part I ordered was TR1516S, which fit the stock steel 16" wheels quite well. They are chrome over plastic, so don't expect old-school metal trim rings. The "360 degree" retainer clips they have give me piece of mind that these aren't going to fly off the first time I hit a bump. I'll post a pic once I learn how.

 

Let's see if this works...