That’ how I would do it:
Raise the rear and support the car on stands. Always keep a jack under the IRS.
Remove the wheels
Disconnect the exhaust joint (in the front of the IRS)
Undo the rear exhaust tips and unhook it from the hangers
Undo the mounts and you can now lower the IRS enough to change them.
As mentioned before keep an eye at the flexible brake line and handbrake cable.
PS
The IRS is front heavy, so having the jack biased to the front helps to keep it straight.