XHD's are 6 leaf springs, the standard OE springs were 5 leaf and ~85 lb/in, the XHD's are 6 leaf and ~110 lb/in. I would suspect that the XHD's are fairly similar in height and spring rate to the ESPO 6 leaf springs, but of course being a different manufacturer there are no doubt some differences.
And give it a harsh ride, uneven ride height in the back, and worse handling in the process. SS springs are great for hooking up drag racing launches, but for anything else they're not the best choice.