Fitted mine in the Defender's engine bay. A bit hot, and as @ChrisW said, she is a bit fussy, so I have to remember to open the hood when using the compressor a bit longer. And probably more importantly, as I found out last night,: DON'T FORGET TO TAKE MY PHONE FROM THE CONVENIENT PLACE ON TOP OF THE RADIATOR, BEFORE CLOSING THE HOOD!!!
I chose to install the little manifold and the Bluetooth controller with it, to make things easier avoid additional switches in the cabin. You can then set programmable pressure options and it regulates it all by itself, though I fail to see the point in reducing pressure via the controller.
The compressor's controller is connected via the Garmin Powerswitch for the same convenience: accessible on the phone and carplay! Again, ensure you put the phone back in your pocket after use, see note above...
The air outlet I led through the side of the car, opposite of the engine air intake, which has no function with my engine, (for people blessed with a bigger wallet: it does with the Octa). Great for access and the normal ARB hose is long enough to get to all tires from that point.
Key takeaways are: make sure you still have sufficient airflow/cooling otherwise it will just stop working in best case until reset, or cease in worst. Ensure you fuse your power supply, for some reason the first fuse blew only after it fried one of the motors in the compressor. Luckily ARB gave me a new one after they did some checking!