I put a set on my year 2000 truck when it was fairly new because with the overload springs the ride was terrible. The difference was barely noticable, but I wasn't about to go through what I had just done in order to remove them.
The theory is a good one, but in practice I haven't noticed much difference. I wouldn't do it again.
The shackles do "bottom out" occasionally, with a noise that is disconcerting, although not too loud. You don't get the idea that the suspension is falling apart, but you definitely know that the shackles hit their limit.
You won't be unhappy with them. You may find that they were not worth the money and the trouble of installing them.
Loren