If you can find others that have them and match a good set to your car you won't be wasting money.
From a race tech chat place.
The term coilover is short for a coil-over-shock setup, where the coil spring is installed around the shock. Coilovers were originally designed for race cars so that the suspension height and dampening settings could be easily changed. Coilovers are installed as one unit instead of a separate spring and shock setup. Though they may look similar in some ways to a Macpherson strut assembly, which is also a spring and shock assembly, coilovers are far more sophisticated.
The springs in coilovers are normally either a single progressive spring or a multi-spring setup with a primary spring and what is known as a helper spring. The helper spring is much lighter and only comes into play when the suspension is at full droop during aggressive cornering. The helper spring ensures the main spring remains stable.
Advantages and Disadvantages
By far, the main benefit of coilovers is the range of adjustment they provide. Coilovers are height adjustable via the spring perches that are threaded onto the shock body. The shocks normally offer a range of adjustability that can include shock compression (the downward stroke) and rebound (the upward stroke of the shock as the suspension unloads) with as many as 15 or more settings for each.
Some coilovers such as Motons feature a remotely mounted reservoir that provides the oil for the shock and also allows easy adjustment without having to jack up the car to access the suspension.
The biggest downside to coilovers is the price, which usually starts at just under $1000 and goes up to over $5000 for some of the higher-end brands.