When I bought my Toyota, it had 2.0 18's on the rear. Never had problems out of them in terms of maxing them out. I ended up switching to 16" 2.5's later on and have had no issues with them either. What I did learn was the way my shocks are mounted, they allow for more wheel travel than if they were mounted more straight up and down (they are semi close together at the top mounting points). When I went to remove the 18's in my shop getting ready to install the 16's, the suspension would not even travel far enough for the 18" shock to extend all the way out so I could remove the mounting bolts, it would start picking up the axle on the side I was jacking up. This was due to the center limit strap. Had to remove the center limit strap then I could get everything to stretch out far enough. This is a good thing, I'm guessing that's what helps my shocks not max out really hard when I'm wheeling. My rig is currently under the knife getting the front 4 linked, but it used to be leaf sprung front. The leaf springs did not allow for very much up or down travel the way they were set up, so I was always flexing the rear like crazy when crawling tough obstacles. So the center limit strap has been holding it back from ripping the shocks apart, I suppose. At static ride height, it only had about 1-2" of slack in it.