The product itself is good. Heavy and solid, will do the job.
One issue I had was that the squared U-bolts that come with the springs are not threaded up far enough. I put the nuts up all the way and still had about 1 and 1/2 inch of slack when the car was still on jacks. When the vehicle was lowered, it took too long for the spring to engage and bear weight. I really would have liked to tighten that U-bolt all the way when jacked so it would help the rear-end be a bit higher.
And one other thing you need to be aware of when ordering this kit, and that is that you need to undo the axle U-bolts and take the top plate off in order to add this spring on top of existing springs. The problem I had was that the axle U-bolts were then too short to put the top plate back on and get a nut started. I had to order 4 new axle U-bolts from another company that were 1 inch longer in order to install these springs. I wish I knew that would be a problem earlier or in their literature at least.