The engine swap and rebuild is finally complete, car is now running and passed MOT. Had to swap the transmission as well in the end, turns out the USDM engine has a slightly different bolt pattern than the bellhousing on the JDM engine. Kept my JDM transfer case as I wanted to keep the two wheel drive mode. I also replaced all the exterior lighting (other than the headlights) with LEDs - had to replace the blinker module as well to suppress the 'bulb fail' warning.

Next things to do;
1) Re-gas the aircon
2) Re-enable the LPG system
3) Replace somewhat rusted exhaust with larger bore stainless one / twin exhaust tips
4) Mount roof rack, replace lightbar with modern LED ones.
5) Get those 18" USDM chrome wheels restored + new tyres, replace the JDM 16" wheels.
6) Mount + wire up USDM side markers.
7) Break the remains of the USDM car for useful parts.

Supercharger is currently dismounted because I haven't found a way to make it compatible with the LPG fuel system yet; still working on this. Looking at a three tone vinyl wrap (stainless upper / carbon fibre on the cladding / 'titanium' on the hood insert). Will eventually get to the interior and entertainment system.

The car has developed a fault post-swap, though it's more annoying than serious. In TOD mode the car starts and drives fine; 4L also works with no problems. However after a few minutes in 2WD mode the rear wheel LEDs blink and the 'check transmission' warning light blinks on the TOD panel. It doesn't seem to affect the transmission at all; the car stays in 2WD mode, the front wheel LEDs don't come on and the TOD clutch doesn't activate. My guess would be a microswitch or wire/contact on the transmission mode selector has failed and the TOD computer is incorrectly activating, even though the transmission is mechanically locked in 2WD-only mode.