It's on the US driver's side, in the "aquarium".  See picture in the Instructions link, below
bulletRemove the aquarium cover and the false bulkhead  Instructions
bulletSlip the brass retaining clip off the ABS ECU
bulletPull the ABS ECU up and out and rotate it out of the way
bulletRemove the mount screw at the bottom of the bracket.  Picture
bulletRemove the two mount screws at the side of the bracket.  Picture
bulletPull and rotate the fuel ECU up and out.
bulletRemove the connector as with the APC/DI ECU
bulletDepress the spring clip
bulletPull the connector loose at the spring clip end
bulletRotate the connector out 90 degrees
bulletDisengage the connector at the rotation end.
bulletFor those who need to open the box

Re-installation

bulletFirst, connect the wiring harness
bulletRotate the ECU into position
bulletThere's a ground wire that goes under one of the mount screws
bulletDon't let it get lost behind the ECU
bulletLocate the mount tab onto the tang on the front of the fixed mounting plate
bulletSlide the hinge tab of the removable plate into the slot in the rear of the fixed plate
bulletRotate the removable plate into position and secure with the lower  front screw
bulletInstall the ground wire under the upper front screw
bulletIt's very helpful to use a small screwdriver or a nail to align the plate/ECU/mount base holes.
bulletInstall the bottom screw
bulletRotate the ABS ECU into position  and secure it with the brass clip