If you don't fancy replacing all 3 of the Control Box fans you can just use a single 120mm exhaust, it has more than enough air flow and will cost a lot less. You'll want to wire the fan to one of the 12v connectors on the motherboard, rather than the PSU (which will only turn the fan on when hot). I've also removed the cover from the PSU for better airflow.
If you don't remove the PSU cover, then please leave the stock PSU fan on. - There's simply not enough ventilation in the PSU casing
The caveat here is you'll need some legs, I'm using Shift31's that can be found here:
Print is 2.2mm thick which is plenty strong enough with PLA. Included option to print in 2 halves, the screws from the fan will keep the peices together but make sure you use a washer for the middle screw (pictured)
This is where you need to power the fan: