SVT driver is correct in that the proper way to cut coil springs is NOT with a torch. This will change the metal characteristics and unless you're prepared to anneal them after, don't attempt this.
If however, you use a hacksaw, reciprocating saw or cutting wheel you'll be fine. I have done this many, many times and never had a problem. There are a couple of details you must address (polishing the cut, no nicks, etc.), but it's actually easy, if you know what you're doing.
The other advantage to cutting your existing springs (other than the $$$'s saved) is that you can calculate how much drop you want and cut accordingly. I didn't want any drop at the rear of my car (camber is already outside factory limit) and a 1" drop at the front. This gave my car a nice positive rake, and the gaps at the tire to fender are almost equal, unlike the stock gaps - huge at the front and nearly correct at the rear.
Also, the aftermarket spring suppliers seem reluctant to supply spring rates. I don't want a go-kart ride so I stick with factory rates because I know what the ride will be like. As long as you do not cut more than 1 full coil off, the rates barely change. Do the calculations....
