i put sir/vti rear discs on my ej6 coupe a few months ago. when your gettin the discs take off the hole trail arm from the donor car, its 5 bolts to drop them out. un-do the cables from the hand brake inside the car and pull the cables out the back keeping them intact with the caliper.
the donor trail arms will simply bolt up like the drums, attach the cables inside and the brake fluid pipe and your set to go. adjust cables inside and if you feel its necessary install bigger master cylinder.