I have 2.5 fronts and 2.0 rears. The 2.5's are softer - but I don't know how they compare to the 2.0 fronts. The rears are too firm for my preference unloaded. With 400lbs in the back - they're great.
I recently did a long distance desert run - 50-80mph through the Grand Staircase. ~120 miles total of dirt travel out and back. I was going out for some canyon exploring, so I was just in a hurry to get there. It's not a hardcore offroad trail - just very washboarded sand/gravel with lots of opportunities to get air born. I stopped both at the end and at the road again and checked. I didn't get anywhere close to overheating either set of shocks. The rears were maybe 200 degrees. The main point being that I don't think I could overheat them doing anything I can in the 4Runner and still keep the shiny side up. As far as heat goes I think the 2.0's are just fine for the suspension setup of the 4Runner.
Not sure what happened to Jetboy, but I will add this here:
Hole in the Rock is a dirt road with washboard and some washouts, but is not indicative enough.
I will be replacing my 2.0 Icon without reservoirs with either 2.0 Fox or 2.5 Fox with reservoirs and adjusters.
The problem with non-resi performance 2.0 is not that they cannot perform very well on the 4R but that mildly rough desert surface, such as any AZ easy trail or something like the Croton road or the middle section of Smokey mountains heats up the shocks to 250F (finally measured that on a dirt road with embedded rock and loose rock in AZ).
Control remained great on a well-paced 60 mile loop with temperatures normally under 200F for the Icon 2.0 (but only 100-110 normally and 130 max for the 6112 front). I had not previously measured temps.
In short, if you have no rear pax, you can get away with a non-resi 2.0. I have done an AZ desert 100 mile run (far rougher than Hole in the Rock) at a nice pace without the kids and had no issues.
But if you do have rear pax, you will want reservoirs and preferably adjusters. The 2.0 just don't have enough volume for the needed oil and gas, heat up too much, presumably pressures go up too much, and the rear pax get beaten up as the effect is that of stiffer springs.
And I don't think my Icon 2.0 will last much longer (13,000 miles now). They are now easy to push by hand. So longevity is another reason to go for the reservoir.
On the other hand, they have been fantastic in rock crawling as is. So much depends on your terrain and on how often you use them.
My post assumes frequent and serious use (meaning long stretches at good pace). Otherwise, no resi needed. Low price: use and get new, repeat.
opcorn:
