Installed the H&R lowering springs on Thursday. Took me just over 3 hours. Hardest part was the upper strut mounts under the hood, until I realized that the plastic windshield cowling comes off and the upper strut bolts then take about 10 seconds to remove.
The lower bolts come off and the strut just slides right out past the rotor. Surprisingly little compression was needed to get the mount unbolted and swap the H&R springs in. Two man job reinstalling the struts - fit the bolts in their holes from the bottom and have a helper thread the nuts on from above to hold the unit in place while you line the bottom up and install the H&R triple C camber bolts!
The rear springs are where I really made up time. The service manual would have you unbolt 8 or 9 things and remove the caliper, rotor, hub, and knuckle. I've attached pictures that prove that process unnecessary.
Basically, just put enough pressure on the arm and spring to relieve the tension on the rear camber bolt and slowly remove the nut locking the adjuster in place , then move to the other side of the arm and spin the adjuster bolt all the way out of its hole. As long as pressure is maintained on the arm just under the spring, the bolt slides out and you slowly lower the jack and then swing the arm down, swap springs and reinstall the bolt and nut. Total time on BOTH rears was less that 40 minutes.
Picture shows the rear camber bolt being backed out (after locking nut was removed from the opposite side) and the arm swinging down for the spring swap.
Easy stuff...