I had found this excerpt from an xterra forum but ADO claims this isnt accurate after reviewing it "But, to sum it up - As soon as you stick higher rate springs on those 5100's, the rebound damping will be wrong. If you put longer springs with a higher rate (the OME MD and HD), you'll not only have problems with rebound damping, you'll also be introduced to the dreaded 5100 top out clunk.
Here's why - and I'll try to make this short.
Rebound damping for any shock is dictated by how fast the engineers want the suspension to rise back up after the suspension is compressed. As soon as you change to a higher rate spring, you've increased the force extending the shocks. More force = faster rebound. The damping won't be enough to slow the suspension from extending too quickly and the suspension will "bounce" up too fast.
Increasing spring length (keeping the rate the same) will mean the spring will have to be compressed more than a shorter spring, just to get it to fit on to the shock. When the shock is fully extended, that longer spring will be applying more force to the shock than a shorter spring. This force is Preload. More preload on a spring = more lift, BUT, it also means that the spring is applying more force trying to extend the shock. Sound familiar? That's because it's the same problem you have with a higher rate spring. Too much force and the rebound damping is not enough to slow the suspension down when extending.
If you put OME MD coils on a 5100, they are longer AND have a higher spring rate. While the truck will sit higher, you're going to end up with a suspension that is underdamped and will bounce - resulting in a less than ideal ride.".
Would be interested in others' thoughts. Might end up making a separate post about it.