if you can do the front end the rear will be easy as for you, this is how i did my d22.
jack up one side of the car well more than needed to allow for the lifted spring (if you got a lifted one), take wheel off, place another jack under the axle at the end so it doesn't plonk to the ground and also adjust it up and down, undo and remove the u-bolts, lower axle down a bit for clearance of the spring, undo pin and remove, undo shackles and remove, remove old spring and presto
put new spring in and install the pin, swing the rear up and do the shackle up, adjust axle with jack to where it has to go, install u-bolts and put the wheel back on and start on the other side
just make sure u put the springs on the correct side as there's a drivers side spring and a near side spring