Before considering any major modifications to your 4WD, suspension should be at the top of your to do list.
Without good suspension your articulation, road comfort and clearance on the tracks can be limited or non existent. This makes it difficult to complete even the simplest of tracks. Not to mention that adding additional weight such as a bull bar and winch, roof rack and or a rear bar can cause your original suspension to sag.
When we bought our 70 series it’s suspension had been upgraded but it was getting pretty tired, which limited us in some areas and it did not tolerate load well. Because the Landcruiser is so capable off-road we didn’t realize the extent of the sag until we put the new suspension on. To explain, we gained and extra 45mm in ride height without installing extended shackles.
We opted for the EFS suspension from Force4 owned by Phil Clark . We highly recommend going to see Phill if you are looking to upgrade your suspension, he seriously knows his stuff and he has some of the best customer service in the industry.
When installing our suspension we took out two leafs from the rear leaf pack. This was recommend by Phil as the pack was made for the 4 door 75Series which is larger and heavier than our Landcruiser. Removing the 2 leafs made the ride less stiff and more comfortable for road driving.
Installing the new suspension was pretty straight forward but having an extra set of hands is not a bad idea. We had trouble with one of the shackles as it was put in backwards. This made it hard to remove when installing the new bushings. But don’t worry we reinstalled it in the correct direction. We also stripped the front left shackle whilst removing the old 
suspension as it was seized! This was a problem when it is 10pm at night. But thank God for friends with Landcruisers, we were able to grab a spare from our friend with a 40Series and complete the job the following morning.
