Some of the body kits, like the Wings West one for example, have part of the sideskirts that come up above the rocker panel behind the door on the ZX3's. Also, the back bumper will not fit because the sedan rear bumpers are longer due to the trunk.
All Foci are the same from the front to the back of the back seat. This includes wheelbase, width, etc... The difference are all AFTER the back seat. Any side skirts that don't go up into the body panels will work on all Foci.