There might be a difference due to the fact that the XLR factory wheels accomodate the run flats and the SRX wheels do not. I have both an XLR (05) and an SRX (05). The SRX wheels look almost identical to the XLR wheels. Unfortunately, I don't have my XLR factory wheels to compare since I recently bought the Vogue Speedster chrome wheels and my old X:R factory wheels are at the shop (going to be returned, but just haven't picked them up yet).
I know the shop had some trouble getting the Vogue Speedster chrome wheels on the XLR with the run flats, but they were able to get them on with a little creativity.
The biggest difference is the SRX wheels are 6 lugs and of course our XLR's are the standard 5 lugs. I have since noticed that people are selling SXR wheels as XLR. Not only is the bolt pattern different but there is a big price difference. Before anyone gets burned by this situation I wanted to share this info. I know I have 4 wheels enroute to me sold as XLR rims but they are SRX wheels. I got to see how I put a 6 bolt wheel on a 5 bolt hub! Oh well live and learn, and by sharing this we all can learn from my mistake. Now how to you spell refund!