For anyone challenged with installing the Springlift struts used to hold the external storage bays open. We had to replace one on our '03 this past summer. The numbers on the old strut should tell you what psi they are, I think ours was 120psi. The factory can also tell you.
We found a 24“ QuickGrip clamp worked great to compress the strut to the proper length allowing it to pop right on the pins. The most common clamp models are rated for 300 lbs, which was plenty to compress the 100-120 lb. strut. A pipe clamp would work as well or even a ratcheting tie down.
We opened the jaws of the clamp so that the entire length of the strut fit between the jaws. End to end. That's why we used the 24” clamp. The strut has a 12-20“ operating length so you need a clamp that can start with the strut uncompressed (20”). Then squeeze the handle to compress the strut, support the strut while you do so. You only need one hand to operate the clamp so the other is free to make sure the strut is properly lined up.
The clamp compresses and holds the strut to the correct length. We basically had the strut and clamp almost in place before starting to compress it, so we could make sure it was aligned correctly and didn't have to carry around a compressed strut. Hold the door in a position that allows access to the strut mounting at both ends while not needing to compress the strut any more than necessary. Some owners compress the strut and then place it in a wooden doodad / helping hands to hold it compressed and maneuver that into place.