I have a combination lift. I did have a Rocky Road 2 1/4 lift using the spacers. After increasing the weight of the rear of my Commander with a diamond plate storage compartment and an additional 30 gallon auxillary gas tank, I installed Superlift 4 inch replacement coils springs on the rear and took off the rear spacer. I was bottoming out with the extra weigh when using the stock springs. I think Jon need to add another choice to his poll.