I have some replacement perches, do you think I can compress the spring and push the shock down and slip these on or will I have to take off the whole coilover?
You're gonna have to take the coilover off the car since you gotta remove the strut mount to remove the spring & then ultimately remove the perches.
It's not hard since the Koni coilover is so short though. Lube up the base of the strut, remove the swaybar endlink nut (might need to soak that stud), remove the strut pinch bolt & nut, insert strut spreader bit, give it a swift kick to loosen it/drop it down from the hub, then remove the 3 bolts on top & it'll come out.
If you can spin the perch all the way to the bottom (or close to it), you won't even need to compress the spring to remove it (there won't be much pressure on it). Remove the strut nut, remove the mount/bearing, remove spring & then remove the old perch.
And then when you go to reassemble, set the dampening to full firm, pull the strut rod all the way out, spin the new perches down, put the spring back on & you will just have to lightly push down on the strut mount so you can start the nut back on. Then tighten it with a wrench from there
Antiseize on some of these parts will be your best friend in the future as well