Icon Vehicle Dynamics 2.5 adjustable coilovers are available for many makes. I installed a set of the extended travel with the optional corrosion protection designed to be used with aftermarket uniball upper control arms on a 2000 Toyota Tundra Limited Access Cab.
These coilovers are race bred and it shows. Formally Donahoe Racing, these 2.5" diameter shocks have been designed and tested extensively. The 2.5" diameter displaces heat better than the previous 2.0 version. The adjustment range on these are from stock height up to 2.5" of front end lift. They come pre set around 2" of lift. I found a happy place just lower than the preset. There are many benefits to the adjustable coilover with the obvious being ride height, but more importantly you can adjust the preload to really dial in your handling. The higher you go, the more compressed the spring becomes and the stiffer the ride. You can also adjust left to right to level the truck. I had these mounted with Camburg Uniball Uca's (seperate write up) for slight additional negative travel and a custom set of progressive 500lb over stock Alcan leaf springs.
The Performance increase was very noticeable both on the road at highway speeds with hugely improved low speed compression that handled the pitch and roll of the vehicle as well as high speed compression for sharp hits off road. The faster you go off road the more you notice how well they dampen the ride. They really change the off road handling of the Tundra and I also really noticed an increase in traction and better handling on rough snow packed roads that become almost wash board like.
I drove this set up for about 10,000 miles and was very happy with there performance. As with all suspension modifications there is a change in handling and geometry and should be installed by a qualified mechanic.