Hi!
I've finally registered here and will be able to provide some clarifications. Unfortunately accessing this forum is a bit convoluted from here, so I won't be posting too often.
The DirectX 9 mod is generally intended to be used with WOFF, but since people still play CFS3 I will be trying to keep it compatible as well. Currently main issues are reflective surfaces and cockpit lights which weren't implemented because they aren't used by WOFF. There are also some glitches with certain 3rd party models as mentioned above.
I'm working with gecko and MajorMagee to improve CFS3 compatibility, so eventually I hope to get rid of all these issues.
Minimum system requirements for self shadowing are AMD HD 4xxx series or NVidia 8xxx series. These cards are from around 2008, so I believe it is not a problem for most people. Modern built-in Intel graphics should also work, but they are quite slow. I'm using Windows 7 for development and haven't tested it on XP, but I don't know any reason why it shouldn't work there.
The first thing to try if the game fails to start with my mod is running cfs3config.exe and selecting screen resolution again.
And just one more note - although my mod enables the use of SweetFX, it is not connected to it in any other way