Very good photos and I wish i knew how to get this good image quality.

According to my real life tests, it seems d-range helps when shooting in bright conditions, but may introduce noise in shadowy places. I usually shoot jpegs so when I need to try get some blown details back to life I use Paint.net's shadow/highlight recovery tool, which often does a good job.

Posting this link just in case you haven't tried these tips

http://forums.dpreview.com/forums/read.asp?forum=1036&message=29213895