Okay, will do this after this post.
Intel i7-3770
Asus P8Z77-i WD
Nvidia GF GTX 770
I managed to get into safemode after renaming the kext
It finishes the update and I could login (still in safemode)
After that I ran Multibeast (6.2.1) with my saved settings and then I ran kextutil.
Reboot.
Now it takes a bit long to boot up but I only get a black screen.
"com_driver_gxxxdriver:
robe fails"
I think that wasn't there before.. not sure
Edit: For those who (hopefully not of course) might face the same problem:
1) Get into safe mode (-x)
2) Run Multibeast with your saved configuration
3) I installed the newest FakeSMC.kext CPUSensors.kext and GPUSensors.kext (from HWSensors package) with kextutil
4) Fix permissions with diskutil
5) reboot
I think Step 4 fixed it for me, as I did step 2 before with no success and step 3 is not related I think, not sure though