A Hyperflow intercooler from Australia is used on the Spec C. Not because it was a spectacular performing kit or anything, but really just because it was black. Being black kept the Spec C looking as low profile as possible. From the entire front mount intercooler kit, only the core, two brackets, and two hoses were used.
From across an intersection the front mount intercooler probably isn't even visible. The Spec C engine oil and transmission oil coolers both had to be relocated to fit the FMIC core.
Most of the mechanical work on the Spec C was completed at Litchfield Imports which is known these days as one of the UK's premiere R35 GT-R builders. At one time they were best known for their Cosworth engined Type-25 Imprezas.
Here the fly by wire throttle is on there now with an adapter plate. The chamber in the intercooler pipe is actually the boost control chamber. The SQ6M ECU regulated pressure from this chamber to blow shut the wastegate. On top of the intercooler tube right before the throttle is a pressure sensor. Ben's had as much as 3.8 bar absolute before the throttle.
It looks like a size 16 or larger Autosport connector is used for the sub-harness to wire all of the other sensors, solenoids, and motors that the factory wiring harness doesn't support. With the STi strut tower bar in place, it's barely visible.
The sub-harness is properly done like a motorsport grade harness with Autosport connectors where possible, Raychem DR-25 heat shrink, Raychem boots, teflon wire, kapton tape, etc.