http://www.toyota-4runner.org/5th-gen-t4rs/
XReas is on all Limited models. If you don't like it, you can replace the shocks and leave the XReas plumbing behind, many have.
KDSS is an option on Trail Editions. You can tell by the yellow KDSS light in the instrument cluster when you turn the ignition switch to on, and before you start the engine. You can also look down at the front lower control arm. If there is a bigass swaybar connected to the LCA, it is KDSS. The others have smaller sway bars that connect to the knuckle.
KDSS:
Not sure why you wouldn't want KDSS. Has thicker sway bars for improved handling on road, and it "effectively disconnects" them at low speed for better articulation.
The BMC is going to depend on your wheels and caster, mainly. Negative offset and wide aftermarket wheels will almost certainly cause rubbing on the body mount. I am running 285/70/17 MTRs on 8" wide 4.5BS 0 offset wheels, even with 5.5 degrees of caster, I had to cut the body mount.
If you're having to shift to 3rd in your Taco, you will on the 4runner, also. It has an updated dual VVTI version of the 4.0 in the Taco (actually makes more power than the old 4.7 V8), but it doesn't make any more torque at low RPMs than the old engine. It has the same trans and gear ratio as the Taco, but weighs a lot more.
I recently changed to 4.56 gears (stock is 3.73), and it is great, now.