I've been cutting springs for a long time, first car I did was my new 1986 Dodge Daytona. So I'm looking at, what, 18 years doing it.
Works fine, except for two things. First is that your car sits lower to ground. How much depends. If you are doing it yourself and you cut too much off you can't do anything about it except buy new springs. If you have a less than popular car (re my Daytona) you are stuck buying new springs from the dealer, $$$. So you either need to ask around and see who's done it and what they did and got, or cut a half a coil at a time and reassemble and see if you like it or just cross your fingers, cut it and live with it.
The second thing is that it will increase the spring rate. Which means the car will not ride as smooth as it did. But if you look at all the lowering springs offered by everyone they all increase the spring rate.
Buying a set of aftermarket lowering springs net's you one thing, someone else's time to figure it out.
Cutting your stock springs is fine as long as you do not cut too much off, don't want your spring to fall out when the suspension is at full droop, and you do not use too much heat. So using a torch is out. A high speed cutoff wheel is the ticket.
Steve