Don't mean to revive an old thread but I wanted to give my take on the American Humvee Springs just in case anyone else looked up something similar.
I am quite certain I was one of the first sales outside of close friends and his own testing. I bought them back 2018. I was mainly interested in them because I wanted the lift to help clear 42's. Ride improvement just happened to be byproduct.
Ride quality: I test drove my Humvee for around 10 minutes. Bought it. Brought it home and immediately put it on the lift. That was the only experience I had on the factory springs. Which by the way, I had the HD rear springs. Once the AH springs were installed, I thought it rode OK. As expected, honestly. I spoke with the guy on the phone for quite some time and he explained that the reduced spring rate (struggling to remember here... 720 or 740 lb/in I think it was) will ride much better than the stock Humvee springs. But, the AH spring rating it is the equivalent to a 1 ton truck. So it will still be stiff. And I 100% agree with that. It rides just like a 1 ton truck. But do not expect a cushy Cadillac ride.
Lift: They definitely cleared the 42's perfectly. Left just enough fender gap they didn't seem stuffed. However, when I installed the springs, the lift was so much that with the shocks fully extended, the eyelet was 2" below the bracket bolt hole. I had to literally jack up the opposite corner of the vehicle in order to compress the spring in order for them to line up for me to install the bolt. I drove it like this for a week and took it all back apart because I couldn't stand driving the truck around with the shocks in full extension, only working in compression and then slamming back into full extension. Anyway, I pulled them out and welded on extensions to the mounting bracket. This helped put the shock back in stock riding position and help with ride quality obviously. I had called the guy to let him know that I had to build the extensions, as he was awaiting feedback from me on how I liked the springs. He was surprised because up until this point he had never had this issue. We chalked it up to the fact I had a barebones 998 and that it was much lighter than anything he had previously tested on.
I paid $1000 back in 18'. I see the prices have gone up. Would I do it again? No. They were an absolute pain to install. I had to ratchet strap both A arms out of the way in order to get enough clearance to even shimmy the spring into place... and that's with the spring having been compressed in my 120 ton shop press then steel banded in 3 places. All this being done on a lift too, so optimum work around efficiency. Not my first rodeo wrenching either. Former master tech, automotive engineer now. I know body lifts aren't the greatest because the gaps do look dumb. But, if I were to build another and wanted to run 42s again, I would just do small body lift and add coil spacers and live with the poor ride quality. It is a Humvee after all.