Updated/installed using pacifist, rebooted, and was presented with my lovely desktop, along with QE/CI, and the whole nine yards.
For anyone else wanting 10.5.7, definitely use pacifist, and do not replace/overwrite your graphics/sound/network drivers.
Files you should also not install:
AppleHDA.kext (if you use modified hda audio drivers)
AppleHPET.kext
AppleIntelCPUPowerManagement.kext
AppleSMBIOS.kext
AppleTyMCEDriver.kext
Seatbelt.kext
System.kext
mach_kernel
mach_kernel.ctfsys
