I didn't much like the stock hubcaps, and I had to remove them to put air in my tires so I left them off.
I'm thinking about the trim rings until I can buy other wheels. I'm considering these ones: http://www.hubcapmike.com/trim-rings-smooth.html
...since they're shown on an XB2 I assume they'll fit; I read somewhere there were issues with some of them clearing the TPMS valve stems.
Anyway, I have a question for anyone else who put the trim rings on. When I took off the hubcaps I noticed on each wheel there is a little straight piece of metal, something like 1/8" x 1" welded on each wheel in the area where the trim ring would grab the wheel, close to the valve stems. I don't know what it's there for unless it's something to help align the stock hubcaps. Did this piece of metal cause any problem with the trim rings fitting properly?