Start Terminal.app and type:
sudo nvram boot-args="kext-dev-mode=1"
Verify that command works by typing:
sudo nvram -p | grep -i boot-args
You should see a line:
boot-args kext-dev-mode=1
Now reboot. If you plug in your razer stuff after the reboot you should see the following in Console.app:
19/09/14 11:12:05,837 com.apple.kextd[19]: kext-dev-mode allowing invalid signature -67023 0xFFFFFFFFFFFEFA31 for kext "/System/Library/Extensions/RazerHid.kext"
You're the man! Been searching high and low to figure this out. Mind if I post this on Google Plus?