This is how i updated to Mavericks
First i bought a second harddrive (in case i wanted to roll back to my old machine).
Followed the default setup guide.
http://www.tonymacx86.com/374-unibeast-install-os-x-mavericks-any-supported-intel-based-pc.html
With the current version of unibeast (3.0.1).
Booted from USB with the following parameters:
GraphicsEnabler=Yes PCIRootUID=1
Else it would stay stuck on a black screen. After i waited long enough it would eventually start the Setup.
Multibeast setup:
QuickStart -> EasyBeast
Drivers -> Audio -> Realtek ALCxxx -> Without DSDT -> ALC889
Drivers -> Audio -> Realtek ALCxxx -> Without DSDT -> HDAEnabler
Drivers -> Disk -> 3rd Party SATA
Drivers -> Disk -> Trim Enabler -> 10.9.0 TRIM Patch
Drivers -> Misc -> ElliotForceLegancyRTC
Drivers -> Misc -> EvOreBoot
Drivers -> Misc -> FakeSMC v5.3.820
Drivers -> Misc -> NullCPUPowerManagement
Drivers -> Network -> Realtek - AppleRTL8169Ethernet 2.0.6
Drivers -> System ->AppleRTC Path for CMOS Reset
Bootloaders -> Chimera 2.2.1
Customize -> Boot Options -> Basic Boot Options
Customize -> Boot Options -> GraphicsEnabler=Yes
Customize -> Boot Options -> PCI Root PCI Fix
Customize -> Boot Options -> Use Kernel Cache
Customize -> Boot Options -> 1080p Display Mode
Customize -> System Definitions -> Mac Pro > Mac Pro 5,1
GraphicsEnabler=Yes
PCIRootUID=1
Perhaps i didn't need that all, but it works.