New springs?
rear (15min job)
stick head under car
undo 18mm bolts on bottom of rear shocks (1 per side)
jack up rear of car
pull springs out
put in new springs, seating correctly on the rubber bits
you will have to lower the car bit by bit until the springs locate ( a mate is useful here)
put bolts back in, job done (use jack to help you line shock holes up with rear subframe holes)
front
BEFORE you jack the car up loosen wheel bolts and the 2, 21mm top mount caps under the bonnet (soak them in WD40 the night before) don't remove them completley yet
jack up BOTH sides of the car (do this off the box section under the car, NOT ON THE SILL!) and put on axle stands
remove wheels
undo lower shock bolts (18mm)
when the shock is free, remove it by pushing the lower part towards the rear of the car (between the steering arm and the wishbone)
once off the car undo 17mm top nut (if its a 172/182, there's no need for compressors)
bang on new spring and reverse the above process for refitting.