Well, I'm going to make an educated guess and say that since the similar SDK was released it would be a good idea to install this since it is probably required for those new releases based on said SDK. I'm not 100% certain on this but it's the guess I'm going with until I hear otherwise.

its exactly the same DX9.0c you already own ... but it adds some dev files..... very very few game do need these ... I have only seen one game up to now and that was the NFS MW demo

True, but you stated a recent popular demo that aleady requires the update. Next month, maybe a couple more demos and more and more each month after that. If it's basically the same as the current DX install with some additions, and with no reported problems as of yet, it seems safe and simple to just install now while it's fresh on the mind instead of searching the internet later when you're ready to just load up and play.

Just wondering if anyone else gets the missing system.dll message when running the DirectX Diagnostic Tool? I might have always had this even before installing this update. What I've read it might be related to installing Net Framework which has a file by this name in it's folder. Both 1.1 and 2.0 I believe. It doesn't seem to affect any games or such. It might be a problem with the Diagnostic Tool.

nope .... no problem here with and without the redist