Thanks David. When you ordered your springs could you have gotten them stiffer? If you could would you want them any stiffer than they are now. I may be using the wrong lingo here as I am new to this.
You can order them any way you want them.
Most of the perceived softness in the 4Runner suspension is from the front coils. The rear coils were designed to handle a moderate load and as such they really don't feel too soft.
The front Icon coil over springs are stiffer than stock - how much I don't know. The rear Icon springs are not supposed to be stiffer than stock, just lift springs. If you install the way the front/rear are delivered from Icon you should have ~2.5" lift in front, 2" in rear. The front to rear height difference is unchanged - just lifted.
When you do what I did, and lift the front ~2.125" and the rear 0.75" it does shift the weight balance of the vehicle slightly to the rear (which is fine, because the weight is biased towards the front to begin with). Shifting weight to the rear makes the rear coils feel softer (because they are carrying a greater percentage of the total weight). You can add spacers to the rear coil to get the same height, but the rear is going to still feel soft because of the leveling effect.
The rear coils on my 4runner were intended to restore that taught balanced feeling lost due to leveling and adding the stiffer Icon coil springs up front. I consulted with both Icon and Deavers before I ordered anything and listened to their recommendations. The coils are 1/2" taller than stock and 15% higher spring rate, yielding 0.75" total lift in the rear. I think the balance between handling, ride and load carrying capability is perfect and I wouldn't change a thing for this type of lift. I made a camping road trip to Big Bend with a buddy this past year and we were LOADED! We had 4 large bags hardwood firewood, 72 qt ice chest full, bags of groceries, drinks, propane, stove, heater 10x14 Canvas Kodiak tent (heavy!), cots, sleeping bags, chairs, tables, gear bags, extra boots, camera gear, hiking backpacks, sticks, a partridge and a pear tree!
The rear sank about 1.5" fully loaded with a full tank of gas. We ran Black Gap road, river road west in the national park, some minor scenic trails in the state park and the road to Chorro Vista all without incident or handling like a bloated overloaded pig.
HTH
David