I do not like the JubJub argument from Roux one bit.
Jub Jub's crime was negligent killing, and this is addressed by the sentence. The crime of intentional street racing is 'ancillary'. OP's crime is negligent killing, and this should be addressed by the sentence.
OP's negligence is even greater in my view. His gross negligence began at the moment 'the window opened' and he negligently believed he was entitled to use lethal force. Once your negligence allows you to kill, that's it.
It is legally and intellectually dishonest to compare OP's case to someone who may have been alone negligently dealing with a real intruder.
It is so important for Nel to make this point about how OP is grossly negligent. The court so far has not said OP was negligent by act of omission - not considering and checking it was Reeva - that will amaze the general public I feel. Just my opinion.