A few weeks ago, I purchased a set of Airlift Loadlifter 5000 air springs for the rear of our Tundra.
Had a chance to use them proper and it has made a big difference to the handling of the Tundra and overall easier towing. We can now keep the nose of the Tundra at the same level when not towing/unloaded and the steering is pretty much back to normal.
I decided on 'manual' inflation, for each air spring, I routed the air line to the bottom front of the rear side tray panel, where I can attach my portable pump which is fitted with an air pressure gauge, works a treat.
Installation was pretty straight forward with no drilling required.