One man's opinion here, but don't waste your time with a spacer lift. The major flaws with a stock 4Runner are nose diving during braking, body roll/sway when cornering, a narrow stance, and crappy tires.
Spacer lifts allow for bigger tires but don't help with the nose diving or sway/roll.
A proper suspension lift, wheel spacers, and proper tires turn a mushy driving experience into a super tight, yet slightly stiffer set up. A WAY better ride as far as Im concerned.
Again, just my 2 cents...