we did front first so...
-jack whole front of the car up so both wheels are off the ground.
-lock wheels one direction.
-undo bottom bolt.
-undo top 2 bolts.
-slide coilover out.
-reverse steps to install new coilover.
rear
-jack up rear of the car at the diff (make sure front end is down)
-take back seat out (can leave bottom part in the car to kneel on)
-slide parcel shelf out.
-take 2 brackets out that support parcel shelf.
-undo top bolts.
-undo bottom bolt.
-slide coilover out.
-revers steps to install new coilover.
job done. it was easier than we though, maybe 2 hours work?
to adjust heights
use general measuring skills on the coilovers.
-jack front of the car up so wheels are off the ground.
-undo bottom bolt and turn bottom section of the coilover up or down (after loosening the bottom location ring to desired height)
no need to take any wheels off for adjusting heights.
same with back.
if the guard is about 20mm higher than the tire when locked then it should be fine i think.
you may hear scraping noises, but make sure you check that its not just the inner guard scraping on the tire, it does this for me. fix = screw a self tapper in the plastic where its scraping.
increasing stiffness should stop scraping if the wheel is to big, if you hear bits of scraping as you go over bumps then yes it possibly will help