Ya, it's compatible with XPS2, I had it running for few days and uninstall it.
I prefer to have my fans controlled by the BIOS, as default.
You mean my link for clean install software? Ya, it's for XPS2's.
About graphic drivers, you could try the 77.72 ones, they are better then the modded 80.40 ones. Many people who tried them, did not liked them at all.
I tried several drivers and ended up using the default ones from Dell. I'm very satisfied with them. If I would be you, I would simply use them. My 3DMarks on a default not OCed card are 5050-5060. It's true, I'm lucky to have a NV41 6800U model that came with the laptop, which is much better then the recent NV42 that is shipped, regarding the performance...
One thing you need to remember. Once you install a video driver, if you change your mind and want to update with another driver, you really need to make sure you properly clean your computer from all the extra file leftovers. I use for that Total Uninstall, but there are many other programs out there that do a driver uninstall/cleanup properly.