Today, I tackled installing Firestone Ride-Rite helper air bags. To me, the instructions were VERY vague. The hardest part was running the air line. Instructions said to run it through the box frame and through the 3/8" hole in the top spring holder. Seriously? I fed the line though the hole and who knows where it is going. The only access hole near the springs is on the outside of the frame, and much too small. Well, I opened the hole a bit, painted it, and was able to get my finger in there to fish our the line. If I had a wire fish, I may have been able to fish it out without opening the hole.
The other thing, drilling the 3/8" hole wasn't easy. The boomerang limited the amount that the axle would drop. Luckily, I found a short enough 3/8" drill in my assortment that was just long enough for the job. And still, it was a pain. I was wishing I had a right angle drill at that point.
One last thing, it didn't state wear to put the heat shield. I figured where the exhaust is closest to the spring. Of course you have a curve there, but a little bending, I got it done. I am debating on putting some header tape in that area.
Here is a few picks of the installed product.

Right side with the heat shield.

Left Side

Filling station.