This topic has been beat to death on this forum. Here is one of the many posts about it, and why I advise people that if they want the 4WD "look" to buy a 2WD truck.
"People like to use lift blocks or spacers under the coils to raise, or shorter coils to lower vehicles with independent suspensions, but I always advise against the practice. While it's a relatively easy and cheap way to change the ride height, the practice has several things to consider if you are trying to change the height by more than an inch. Here's why I say this.
When the factory designs a suspension, they have the control arm bushings, ball joints, shocks, bumps stops, etc. in the center of their travel at ride height. The control arms are fairly parallel and level to the ground. When you change the ride height by much more than an inch in either direction, several things happen. Many times the vehicle starts hitting the bumpstops, so people trim or remove them, which is not a smart move - they are there to protect the ball joints, shocks, and control arm bushings from damage from overtravel. It is not good practice to run the suspension parts near the limits of their travel at ride height, which is the result of the coil length change - it leaves them much more prone to early failure from wear or pot-hole damage. Also, due to the control arms being different lengths, changing the ride height changes the caster, and it can be hard to get a proper alignment. And one item the forum gurus never seem to consider is something that is always mentioned during PROPER control arm bushing replacement. When bushings are changed, it is very important to have the vehicle at ride height before tightening the control arm fasteners, so they are in a neutral position - failure to do so leaves the bushing elastomers under constant twist and much more likely to tear or wear out rapidly. Yet I have NEVER seen where anybody recommends relaxing the bushings by loosening the control arm fasteners and re-tightening them at ride height after changing the ride height.
This is IMO why changing the ride height (more than an inch) by chopping the springs or putting coil spacers in the 2wd trucks is a bad idea. While it is more expensive, using drop or lift spindles is a much better way of changing ride height, since they don't affect suspension geometry."
