There are essentially two ways to lift your 1987-95 Jeep Wrangler YJ: suspension lift or body lift. Each has its pros and cons in terms of price, performance, and ease of installation, but let's first distinguish between the two.
A suspension lift raises the vehicle's frame (chassis) away from the axles by replacing the springs with taller (or more arched) springs. A body lift raises the vehicle by lifting the body away from the frame with spacers. This keeps the frame at its existing distance from the ground. A suspension lift is recommended for anyone planning to use their vehicle off-road while a body lift is recommended for anyone that wants to make their vehicle look lifted with no true intentions of going off-road. This does not mean that a body lifted vehicle can not go off-road. It just will not perform as well as a suspension lifted vehicle because it has not gained any ground clearance. Suspension lifts for the Jeep Wrangler YJ typically range between 2-inches to 4-inches (although there are some companies that produce "extreme" kits in excess of this), while body lifts range between 1-inch to 3-inches.
A suspension lift is more complicated than a body lift because it alters all of the suspension components that give the vehicle its factory ride characteristics. Taller leaf springs are typically stiffer than factory leaf springs so the vehicle will have a harsher ride quality than with soft factory springs. Longer shock absorbers will be needed. The vehicle will also have a higher center of gravity because the entire weight of the vehicle (everything except the axles) will now be raised further from the ground. In some cases, the transfer case will need to be lowered and the rear differential repositioned to minimize driveline vibrations as the Jeep Wrangler is notorious for having a short rear driveline that is not enough accepting to increased u-joint angles.
Pros: Increases ground clearance, increased approach and departure angles, allows fitment of larger tires.
Cons: Expensive, longer installation time, drive line angles are increased (more susceptible to vibrations), brake lines need to be re-routed or lengthened, new shocks needed, increased center of gravity.
A body lift is relatively simple in that it primarily consist of a set of spacers that are inserted at the mounting points between the frame and body of the vehicle. This leaves all the heavy parts of the vehicle (frame, engine, transmission, transfer case, etc) at their factory locations so the vehicle's center of gravity (though increased) will not be increased as much as a suspension lift.
Pros: Cheap, can be installed quickly with basic hand tools, allows fitment of larger tires, simple (all components come in a small box).
Cons: Appearance (there will be a noticeable gap between the body tub and the frame), extra leverage is placed on the mounting points, no increase in ground clearance.
Ultimately, a body lift provides no benefits other than allowing the installation of larger tires where a suspension lift is designed for improved performance off-road (while also allowing the installation of larger tires). If you're on a budget and want to make your Jeep Wrangler look like a big off-road rig with no real intentions of ever going off-road, then a body lift would be adequate for you. However, if cost is not a factor and you're looking to make your Wrangler more off-road capable and trail ready, then a suspension lift is the only way to go.
Source by Dorian Jepsen