So I have already bought a majority of the components in my PC (with the exception of the CPU and mobo, in which the latter I'm still deciding on which one to get) and I would like to know if I should be getting any extra fans for the case.
It only comes with 2 120mm fans, one in front and one in back, and so as I have said before, should I be getting any extra fans, if so, what size and where should I be putting them? Thanks in advance.
It really depends of your GPU, CPU and hard drives.
If you're going to use the Integrated graphics of the CPU and 1 or 2 hard drives those 2 fans included are enough.
Adding a Graphics card, overclocking the CPU and adding more hard drives increases the heat. So if you have a GPU, the 2 x 120 mm fans in the front are a must, (I don't know which Shinobi case you have, if you have the side window version and a GPU, the 120 mm in the side will increase the airflow to the graphics card).
The exhaust is the 120 at the back, and if necessary a 120 or 140 in the top.
Give us more information about your rig to give you a proper way to mount the fans.