The "trim ring" is actually the antenna to read the RFID chip in the key. It's only held in there with small plastic clips and can be popped out quite easily.

I experienced a similar problem in my '04 Crossfire Coupe (now sold). In a car that new, I can tell you what it's probably NOT going to be: The key or the tumbler. They are incredibly well made and will probably outlast the car itself. It's most likely the tab from the steering lock not disengaging completely. I was able to get around this problem for a long time by simply turning the steering wheel a bit to the left while trying to turn the key. It actually served as a low-tech theft deterrent system since if you didn't know "the trick," there was no way you were going to get the car started.

I made some pretty detailed posts of my experiences over at crossfireforum.org that may be helpful to you. Here's the link:

http://www.crossfireforum.org/forum/showthread.php?t=15839

__________________
"It's not about how fast you can go, but how well you can go fast."

Bob in Richmond

'97 S320 (LWB), Ruby Red Metallic, 73k miles
'97 S420V, Smoke Silver Metallic, 155k miles