I'm running Snow Leopard 10.6.3 on my Dell XPS 710, have some small problems, network stops working after large transfers of files, if I'm running with all 4 cores, but if I'm booting with CPUS=1, then it works fine. Working on this, have tried a lot of NIC's but the same problem on all of them, think it's not the NIC itself, something else is not "working" as it should, timers or buffers...
I've replaced the sound card to an old Creative soundblaster 128 card, the X-Fi sound card (delivered with my XPS) is not supported as far as I know, don't think it'll ever be.
I've a modded DSDT for CMOS reset and some other fixes, don't remember all of them, but the most important one is for the CMOS reset.
You'll need some kext's for NForce MB, this is a list of the current kext's I'm using
102 19 Sep 2009 AHCIPortInjector.kext
102 19 Sep 2009 AppleACPIPS2Nub.kext
102 19 Sep 2009 AppleNForceATA.kext
102 19 Sep 2009 ApplePS2Controller.kext
102 19 Sep 2009 IOAHCIBlockStorageInjector.kext
102 19 Sep 2009 NullCPUPowerManagement.kext
102 19 Sep 2009 OpenHaltRestart.kext
102 19 Sep 2009 PlatformUUID.kext
102 18 Apr 23:15 fakesmc.kext
Installation was made with a 8GB USB-stick, with the kext-files above Snow Leopard retail 10.6 DVD and Chameleon RC4 installed as boot-loader on the USB-stick. Search google to find guides for making a bootable USB-stick.
About the RAID, remove the raid config in BIOS and set the drives to single drives, then it'll work.